protein

Basicmeaning

Proteinisasubstancewithacertainspatialstructureformedbytwistingandfoldingapolypeptidechaincomposedofaminoacidsina"dehydrationcondensation"manner.

Proteinmustcontaincarbon,hydrogen,oxygen,nitrogen,andmayalsocontainsulfur,phosphorusandotherelements.

Proteinisapolymercompoundformedbycombiningα-aminoacidsinacertainordertoformapolypeptidechain,andthencombiningoneormorepolypeptidechainsinaspecificway.Proteinisthescaffoldandmainmaterialthatconstituteshumantissuesandorgans.Itplaysanimportantroleinhumanlifeactivities.Itcanbesaidthatwithoutprotein,thereisnolifeactivity.

Menlackingproteinrequiresmoreattentionthanwomenlackingprotein.Onceamanlacksprotein,itwillleadtoadeclineinthequalityofmalesperm,reducedspermmotilityandnon-liquefactionofsperm,resultinginmaleinfertility.

Proteinisacomplexorganiccompound,formerlyknownas"朊(ruǎn)".Aminoacidsarethebasicunitsthatmakeupproteins,andaminoacidsarelinkedintopeptidechainsbydehydrationcondensation.Proteinsarebiologicalmacromoleculescomposedofoneormorepolypeptidechains.Eachpolypeptidechainhas20tohundredsofaminoacidresidues(-R);variousaminoacidresiduesarearrangedinacertainorder.Theaminoacidsequenceoftheproteinisencodedbythecorrespondinggene.Inadditiontothe20basicaminoacidsencodedbythegeneticcode,inproteins,certainaminoacidresiduescanalsobepost-translationallymodifiedtoundergochemicalstructuralchanges,therebyactivatingorregulatingtheprotein.Multipleproteinscanworktogether,oftenbyjoiningtogethertoformastableproteincomplex,foldingorspiralingtoformacertainspatialstructure,soastoperformaspecificfunction.Theorganelleforthesynthesisofpeptidesistheribosomeontherough-facedendoplasmicreticuluminthecytoplasm.Thedifferenceofproteinliesinthetype,number,arrangementorderandspatialstructureofpeptidechain.

Aftertheingestedproteinisdigestedandhydrolyzedintoaminoacidsandabsorbedinthebody,itsynthesizestheproteinneededbythehumanbody.Atthesametime,thenewproteinisconstantlybeingmetabolizedanddecomposed,anditisindynamicbalanceatalltimes.Therefore,thequalityandquantityoffoodproteinandtheratioofvariousaminoacidsarerelatedtotheamountofhumanproteinsynthesis,especiallythegrowthanddevelopmentofadolescents,theprenatalandpostnatalcareofpregnantandlying-inwomen,andthehealthandlongevityoftheelderlyareallrelatedtotheamountofproteininthediet.closerelationship.Proteinisdividedintocompleteproteinandincompleteprotein.Proteinslackinginessentialaminoacidsorlowincontentarecalledincompleteproteins,suchasthosecontainedincereals,wheat,cornandgelatininanimalskinsandbones.

Relatedcalculations

Numberofatoms

Aproteinmoleculecomposedofmaminoacidsandnpeptidechainsmustcontainatleastn-COOH,containingatleastn-NH₂,peptidebondm-n,Oatomsm+n.

Molecularmass

Settheaveragerelativemolecularmassofaminoacidsasa,containingbdisulfidebonds,Therelativemolecularmassoftheprotein=ma-18(m-n)-2b

Genecontrol

Nucleotide6ingene

Nucleotide3inmessengerRNA

Aminoacid1inprotein

Compositionandcharacteristics

ProteiniscomposedofC(carbon),H(hydrogen),O(oxygen),andN(nitrogen).Generally,proteinmayalsocontainP(phosphorus),S(sulfur),Fe(iron),Zn(zinc),Cu(copper),B(boron),Mn(manganese),I(iodine),Mo(molybdenum),etc.

Thecompositionpercentageoftheseelementsinproteinisapproximately:carbon50%,hydrogen7%,oxygen23%,nitrogen16%,sulfur0~3%andothertraceamounts.

(1)Allproteinscontainnitrogen,andthenitrogencontentofvariousproteinsisveryclose,16%onaverage;

(2)Proteincoefficient:Forevery1gofnitrogeninanybiologicalsample,itmeansthatthereareabout100/16=6.25gofprotein.6.25isoftencalledtheproteinconstant.

Overallstructure

Proteinisabiopolymercomposedofaminoacidsasthebasicunit.Thesequenceofaminoacidsonproteinmoleculesandthethree-dimensionalstructuresformedtherefromconstitutethediversityofproteinstructures.Proteinhasaprimary,secondary,tertiary,andquaternarystructure,andthestructureoftheproteinmoleculedeterminesitsfunction.

Primarystructure:Thesequenceofaminoacidresiduesinthepeptidechainofaproteiniscalledtheprimarystructureoftheprotein.Eachproteinhasauniqueandexactaminoacidsequence.

Secondarystructure(secondarystructure):Thepeptidechainintheproteinmoleculeisnotlinear,butcurled(suchasα-helixstructure)orfolded(suchasβ-sheetstructure)toformaspecificThespatialstructureoftheprotein,whichisthesecondarystructureoftheprotein.Thesecondarystructureoftheproteinismainlyachievedbythehydrogenbondformedbetweenthehydrogenatomontheimino(-NH-)oftheaminoacidresidueinthepeptidechainandtheoxygenatomonthecarbonylgroup.

Tertiarystructure:Onthebasisofthesecondarystructure,thepeptidechainfurtherformsamorecomplextertiarystructureaccordingtoacertainspatialstructure.Itisthroughthisstructurethatmyoglobin,hemoglobin,etc.makethecavityonthesurfacejustholdahememolecule.

Quaternarystructure:Theaggregatestructureformedbythecombinationofpolypeptidechainswithtertiarystructureinacertainspatialarrangementiscalledthequaternarystructureofaprotein.Forexample,hemoglobiniscomposedof4polypeptidechainswithtertiarystructure,twoofwhichareα-chainsandtheothertwoareβ-chains,andtheirquaternarystructureissimilartoanellipsoid.

Connectionmethod

Usingabout20kindsofaminoacidsasrawmaterials,theaminoacidmoleculesareconnectedtoeachotherintopeptidechainsontheribosomesinthecytoplasm.Theaminogroupofoneaminoacidmoleculeandthecarboxylgroupofanotheraminoacidmoleculeareconnectedbyremovingamoleculeofwater.Thiscombinationiscalleddehydrationcondensation.Throughthecondensationreaction,thebondbetweenthecarboxylgroupandtheaminogroupthatconnectstwoaminoacidmoleculesiscalledapeptidebond.Compoundsformedbypeptidebondsarecalledpeptides.

Detectionmethod

Add3mlofeggwhitediluentandwatertothetwotesttubesofAandBrespectively,andthenaddthebiuretreagentAandBtothetwotesttubesinturn.ObservethecolorchangeofthesolutioninthetesttubesofAandB.Theabovedemonstrationexperimentresultsshowthatthebiuretreagentreactspurplewithprotein.

Physiologicalneeds

In2000,theChineseNutritionSocietyrevisedtherecommendeddietarynutrientintake.Thenewlyrevisedproteinintakeisasfollows:

●RNI(RecommendedIntake):referstothemajorityofindividuals(97%~98%)Theintakeleveloftherequiredamount.Long-termintakeofRNIlevelscanmeetthebody'sneedsforthisnutrient,maintainpropernutrientreservesinthetissues,andmaintainhealth.

Metabolismandabsorption

Proteinisinitiallyhydrolyzedundertheactionofdigestiveenzymesingastricjuice,completingtheentiredigestionandabsorptionprocessinthesmallintestine.Theabsorptionofaminoacidsiscarriedoutbytheactiveoperationsystemthroughthesmallintestinalmucosalcells,transportingneutral,acidicandbasicaminoacidsrespectively.Theproteindigestedandabsorbedintheintestinecomesnotonlyfromfood,butalsofromthesheddingofintestinalmucosalcellsandthesecretionofdigestivejuice.About70gofproteinentersthedigestivesystemeveryday,mostofwhicharedigestedandreabsorbed.Theunabsorbedproteinisexcretedinthefeces.

Symptoms

Excessive

Performance

Thekidneyshavetoexcreteingestedprotein.Whenproteinisbrokendown,itwillTheproductionoflargeamountsofnitrogenwillincreasetheburdenonthekidneys.Excessiveintakeofprotein,especiallyanimalprotein,isalsoharmfultothehumanbody.Firstofall,ifyouconsumetoomuchanimalprotein,youwillinevitablyconsumemoreanimalfatandcholesterol.Secondly,toomuchproteinitselfcanhaveharmfuleffects.Undernormalcircumstances,toomuchproteinmustbedeaminatedanddecomposed,andnitrogenisexcretedfromthebodybyurine,whichincreasesthemetabolicburden.Moreover,thisprocessrequiresalotofwater,whichincreasestheburdenonthekidneys.Ifthekidneyfunctionisnotgoodatall,Theharmisevengreater.Excessiveintakeofanimalproteinalsoleadstoexcessiveintakeofsulfur-containingaminoacids,whichcanacceleratethelossofcalciuminthebonesandeasilyleadtoosteoporosis.

Harm

1.Oncetheproteinisconvertedintofatinthebody,theacidityofthebloodwillincrease,whichwillconsumealargeamountofcalcium,whichwillresultinstorageThecalciuminthebonesisconsumed,makingthebonesbrittle.

2.Thekidneyshavetoexcretetheproteintheyeat.Whentheybreakdowntheprotein,theywillproducealotofnitrogen,whichwillincreasetheburdenonthekidneys.

Deficiency

Proteindeficiencyoccursinbothadultsandchildren,butchildreninthegrowthstagearemoresensitive.Thecommonsymptomsofproteindeficiencyaredecreasedmetabolicrate,decreasedresistancetodisease,andsusceptibilitytodisease.Thelong-termeffectisorgandamage.Thecommonsymptomsarechildren’sgrowthretardation,malnutrition,decreasedbodyweight,indifference,irritability,andanemia.Aswellasdryweightdiseaseoredema,andsecondarydiseasesduetoeasyinfection.Thelackofproteinoftencoexistswiththelackofenergy,thatis,protein-heatmalnutrition,whichisdividedintotwotypes.Oneisanutritionaldiseasethatbasicallysatisfiesthecaloricintakebutisseverelyinsufficientinprotein,whichiscalledGasikadisease.Theotheris"weightloss",whichreferstonutritionaldiseasesinwhichproteinandcaloricintakeareseverelyinsufficient.

Uses

1.Proteinisanimportantrawmaterialforbuildingandrepairingthebody.Thedevelopmentofthehumanbodyandtherepairandrenewalofdamagedcellsareinseparablefromprotein.

2.Proteincanalsobebrokendowntoprovideenergyforhumanlifeactivities.

Properties

Amphoteric

Proteinsarepolymercompoundscomposedofα-aminoacidsthroughpeptidebonds.Thereareaminoandcarboxylgroupsintheproteinmolecule,soitfollowsSimilartoaminoacids,proteinisalsoanamphotericsubstance.

Hydrolysisreaction

Proteinundergoeshydrolysisreactionundertheactionofacid,alkaliorenzyme.Afterpolypeptide,avarietyofα-aminoacidsarefinallyobtained.

Whentheproteinishydrolyzed,the"breakingpoint"ofthebondinthestructureshouldbefound,andthepeptidebondispartiallyorcompletelybrokenduringhydrolysis.

Colloidproperties

Someproteinscanbedissolvedinwater(forexample,eggwhitecanbedissolvedinwater)toformasolution.

Whenthemoleculardiameteroftheproteinreachesthesizeofcolloidalparticles(10^-9～10^-7m),theproteinhascolloidalproperties.

Precipitation

Reason:addinghighconcentrationofneutralsalt,addingorganicsolvents,addingheavymetals,addingalkaloidsoracids,asmallamountofsalt(suchasammoniumsulfate,sodiumsulfate,etc.))Canpromotethedissolutionofprotein.Ifaconcentratedinorganicsaltsolutionisaddedtotheproteinaqueoussolution,thesolubilityoftheproteincanbereducedandprecipitatedoutofthesolution.Thiseffectiscalledsaltingout.

Inthisway,thesaltedoutproteincanstillbedissolvedinthewaterwithoutaffectingthepropertiesoftheoriginalprotein,sothesaltingoutisareversibleprocess.Takingadvantageofthisproperty,thefractionalsalting-outmethodcanbeusedtoseparateandpurifyproteins.

Denaturation

Undertheactionofheat,acid,alkali,heavymetalsalt,ultravioletlight,etc.,proteinwillchangeinnatureandcondense.Thiskindofcoagulationisirreversibleandcannolongerrestorethemtotheoriginalprotein.Thiskindofproteinchangeiscalleddenaturation.Aftertheproteinisdenatured,UVabsorption,chemicalactivityandviscositywillincreaseandbecomeeasytobehydrolyzed,butthesolubilitywilldecrease.

Aftertheproteinisdenatured,itlosesitsoriginalsolubilityandlosesitsphysiologicalfunction.Therefore,thedenaturationandcoagulationofproteinisanirreversibleprocess.

Causesofproteindenaturation

Physicalfactorsinclude:heating,pressurizing,stirring,shaking,ultravioletradiation,X-rays,ultrasound,etc.:

p>

Chemicalfactorsinclude:strongacid,strongbase,heavymetalsalt,trichloroaceticacid,ethanol,acetone,etc.

Colorreaction

Proteincanreactwithmanyreagentsincolor.

Forexample,whenconcentratednitricacidisdroppedintotheeggwhitesolution,theeggwhitesolutionwillbeyellow.Thisisduetothecolorreactionofprotein(containingbenzeneringstructure)withconcentratednitricacid.Itcanalsobetestedwithabiuretreagent,whichproducesapurplecomplexwhenitencountersproteins.

Odorresponse

Whenproteinisburntanddecomposed,itcanproduceaspecialsmellofburntfeathers.Usethispropertytoidentifyproteins.

Folding

Thestudyofproteinfoldingmechanismisofgreatsignificanceforretainingproteinactivity,maintainingproteinstabilityandproteinfoldingandrenaturationofinclusionbodies.Asearlyasthe1930s,mycountry’sbiochemicalpioneerProfessorWuXianexplainedthedenaturationofproteins.Thirtyyearslater,Anfinsen'sclassicresearchonribonucleaseAshowedthatunfoldedproteinscanproceedspontaneouslyinvitro.Refoldingisjustthatthesequenceitselfalreadycontainsalltheinformationaboutthecorrectfoldingoftheprotein,andputforwardthethermodynamichypothesisofproteinfolding,forwhichAnfinsenwonthe1972NobelPrizeinChemistry.Thistheoryhastwokeypoints:(1)thestateoftheproteinisinthebalancebetweenunfoldingandthenaturalconformation;(2)theproteininthenaturalconformationisinthelowestenergystateofthermodynamics.Althoughtheaminoacidsequenceoftheproteinplaysacentralroleinthecorrectfoldingoftheprotein,avarietyoffactors,includingsignalsequences,cofactors,molecularchaperones,andenvironmentalconditions,willaffectthefoldingoftheprotein.Thenewproteinfoldsandassembles.Functionalproteinsarenotallspontaneous.Inmostcases,theyneedthehelpofotherproteins.Manyfoldingenzymesandmolecularchaperonesinvolvedinproteinfoldinghavebeenidentified.Theclassicconceptofprotein"spontaneousfolding"haschangedandupdated.Butthisisnotincontradictionwiththethermodynamichypothesisoffolding,butitcompletesthethermodynamicviewpointinkinetics.Intheprocessofproteinfolding,therearemanyforcesinvolved,includingsomeconformationalsterichindrances,vanderWaalsforces,hydrogenbondinteractions,hydrophobiceffects,ionicinteractions,entropy-drivenfoldingcausedbytheinteractionofpolypeptidesandsurroundingsolvents,butWestillknowverylittleaboutthespecificityofthecomplexprocessofproteinobtainingitsnaturalstructure.Manyexperimentalandtheoreticalworksaredeepeningourunderstandingoffolding,buttheproblemisstillunsolved.

Inthestudyofthemechanismoffolding,theearlytheorybelievedthatfoldingisagradualprocessfromthedenaturedstatetothenaturalstatethroughtheintermediatestate,andconductedin-depthresearchonthefoldingintermediates.Itisbelievedthatfoldingisbasedonthermodynamics.Drivenbyasingleway.Laterstudieshaveshownthatthereareavarietyofexperimentallymeasurableintermediatesinthefoldingprocess,andthefoldingproceedsthroughalimitedpath.Thenewtheoryemphasizesthatthereisdiversityintheinitialstageoffolding.Proteinsenterthefoldingfunnelthroughmanyways,sothatthefoldingasawholeisdescribedasafunnel-likeimage,andthekineticprocessoffoldingisconsideredtobeapartiallyfoldedproteinasawhole.Theprogressiveassemblyoftheprotein,andwiththechangesoffreeenergyandentropy,theproteinfinallyfindsitsowncorrectfoldingstructure.Thistheoryiscalledtheenergypicture.Thebumpsunderthefunnelreflectthattheproteinconformationinstantaneouslyenterstheregionoflocalfreeenergyminimum.

Schematicdiagramoftheenergylandscape.Theheightrepresentstheenergyscale,andthewidthrepresentstheconformationalscale.Thereareotherlow-energystatesbelowthefunnel,andthecoexistenceofproteintypesindifferentenergystatesisalsominimized.

Thistheorybelievesthatstructurallyhomologousproteinscanformsimilarnaturalconformationsthroughdifferentfoldingpathways.Humanacidicfibroblastgrowthfactor(hFGF-1)andsalamanderacidicfibroblastgrowthfactor(nFGF-1)Theaminoacidsequencehasabout80%homologyandstructuralhomology(12β-sheetsarearrangedinantiparalleltoformaβ-sheetbarrel).Intheprocessofunfoldinginducedbyguanidinehydrochloride,hFGF-1canbemonitoredIthasameltingsphere-likefoldingintermediate,andnFGF-1unfoldsthroughtwostates(naturalstatetodenaturedstate).Nointermediateisdetected.Thekineticstudyoffoldingalsoshowsthatthetwoproteinsadoptdifferentfoldingmechanisms.Forthesameprotein,differentosmoticpressureregulatorsareused,andthewayofproteinfoldingisalsodifferent,indicatingthatdifferentosmoticpressureregulatorshavedifferentstabilizingeffectsontheprotein.Bothoftheseexamplesillustratethecomplexityofthefoldingmechanismandareconsistentwiththetheoryintroducedabove.

Physiologicalfunction

Constructingthehumanbody

Proteinisthematerialbasisofalllife,isanimportantpartofthebody’scells,andisresponsiblefortherenewalandrepairofhumantissuesmainingreadient.Everytissueofthehumanbody:hair,skin,muscles,bones,internalorgans,brain,blood,nerves,endocrine,etc.areallmadeupofprotein,soitissaidthatdietmakeshumansthemselves.Proteinisveryimportantforhumangrowthanddevelopment.

Forexample,thecharacteristicofbraindevelopmentisthecompletionofcellproliferationatonetime,andthegrowthofhumanbraincellshastwopeakperiods.Thefirstiswhenthefetusisthreemonthsold;thesecondistheperiodfrombirthtooneyearold,especiallyforbabiesfrom0-6months,whenthebraincellsgrowviolently.Bytheageofoneyear,theproliferationofbraincellshasbasicallybeencompleted,anditsnumberhasreached9/10ofthatofhumans.Therefore,0to1yearoldchildrenhaveuniquerequirementsforproteinintake,whichisparticularlyimportantforchildren'sintellectualdevelopment.

Structuralsubstances

Thehumanbodyiscomposedoftensoftrillionsofcells.Cellscanbesaidtobethesmallestunitoflife.Theyareintheprocessofconstantaging,death,andregeneration.middle.Forexample,theepidermisofyoungpeopleisrenewedevery28days,whilethegastricmucosaisrenewedintwoorthreedays.Soifaperson'sproteinintake,absorption,andutilizationaregood,thentheskinisshinyandelastic.Onthecontrary,peopleareofteninasub-healthystate.Aftertissuedamage,includingtrauma,cannotberepairedintimeandwithhighquality,itwillacceleratethebody'sdecline.

Carriertransportation

Maintainthenormalmetabolismofthebodyandthetransportationofvarioussubstancesinthebody.Thecarrierproteinisessentialtomaintainthenormallifeactivitiesofthehumanbody.Cancarryvarioussubstancesinthebody.Forexample,hemoglobin—transportsoxygen(redbloodcellturnoverrateof2.5million/second),lipoprotein—transportsfat,receptorsoncellmembranes,andtransporters.Maintenanceandcomposition

Maintainthebalanceofosmoticpressureinthebody:albumin.Maintaintheacid-basebalanceofbodyfluids.Itconstitutestheneurotransmitteracetylcholine,serotoninandsoon.Maintainthenormalfunctionsofthenervoussystem:taste,visionandmemory.

Antibodyimmunity

Therearewhitebloodcells,lymphocytes,macrophages,antibodies(immunoglobulin),complement,interferon,etc.Updateeverysevendays.Whentheproteinissufficient,thisforceisverystrong,andwhenneeded,itcanbeincreasedby100timeswithinafewhours.

Enzymecatalysis

Thevariousenzymesthatconstitutethebody'sessentialcatalyticandregulatoryfunctions.Therearethousandsofenzymesinourbody,eachofwhichcanonlyparticipateinonebiochemicalreaction.Humancellsundergomorethanonehundredbiochemicalreactionseveryminute.Enzymescanpromotethedigestion,absorptionandutilizationoffood.Ifthecorrespondingenzymesaresufficient,thereactionwillproceedsmoothlyandquickly,andwewillbeenergeticandnoteasytogetsick.Otherwise,thereactionwillslowdownorbeblocked.

Hormoneregulation

Ithastheabilitytoregulatethephysiologicalactivitiesofvariousorgansinthebody.Insulinissynthesizedfrom51aminoacidmolecules.Growthhormoneissynthesizedfrom191aminoacidmolecules(ithasnothingtodowithgrowthhormone).

Collagen

Accountingfor1/3ofthebody'sprotein,itformsconnectivetissueandconstitutesthebody'sskeleton.Forexample,bones,bloodvessels,ligaments,etc.,determinetheelasticityoftheskinandprotectthebrain(alargepartofthebraincellsarecollagencells,andformablood-brainbarriertoprotectthebrain)

Energymaterials

Provideenergyforlifeactivities.

Developmentprocess

Proteinwasdiscoveredin1838byDutchscientistGerritMard.Heobservedthatlivingthingscannotsurvivewithoutprotein.Proteinisanextremelyimportantmacromolecularorganicmatterintheorganism,accountingfor54%ofthehumanbody'sdryweight.Proteinismainlycomposedofaminoacids,andvarioustypesofproteinsareformedduetodifferentcombinationsandarrangementsofaminoacids.Itisestimatedthattherearemorethan100,000kindsofproteinsinthehumanbody.Lifeisanadvancedformofmaterialmovement.Thiswayofmovementisrealizedbyprotein,soproteinhasextremelyimportantbiologicalsignificance.Thegrowth,development,movement,heredity,reproductionandotherlifeactivitiesofthehumanbodyareinseparablefromprotein.Lifemovementrequiresprotein,andproteinisalsoinseparable.

Somephysiologicallyactivesubstancesinthehumanbody,suchasamines,neurotransmitters,peptidehormones,antibodies,enzymes,nucleoproteins,andproteinsonthecellmembraneandinthebloodthatactas"carriers"areinseparablefromproteins.Itplaysanextremelyimportantroleinregulatingphysiologicalfunctionsandmaintainingmetabolism.Thecompositionofmusclesinthehumanmotionsystemandthemetabolismofmusclesintheprocessofcontraction,work,andcompletionofmovementsareallrelatedtoprotein.Withoutprotein,physicalexerciseisimpossible.

Inbiology,proteinisinterpretedasapeptideformedbyaminoacidslinkedbypeptidebonds,andthenasubstanceformedbylinkingpeptidestogether.Itiseasytounderstandthatitisthescaffoldandthemainmaterialthatconstitutesthebody'stissuesandorgans.Proteindeficiency:Adults:musclewasting,weakenedbodyimmunity,anemia,severecaseswillproduceedema.Minors:growthretardation,anemia,poormentaldevelopment,andpoorvision.Excessiveprotein:Proteincannotbestoredinthebody,andthebodycannotabsorbtoomuch.Excessiveintakeofproteinwillcauseproteinpoisoningorevendeathduetometabolicdisorders.

Classificationinformation

Thenutritionalvalueoffoodproteindependsonthetypeandquantityofaminoacids,soitcanbedividedintocompleteproteinandsemi-proteinaccordingtotheaminoacidcompositionoffoodprotein.Therearethreetypesofcompleteproteinandincompleteprotein.

Completeproteincontainsacompleterangeofessentialaminoacids,sufficientquantitiesandappropriateproportions,whichcannotonlymaintainthehealthofadults,butalsopromotethegrowthanddevelopmentofchildren,suchascaseinandlactalbumininmilk,andineggs.Ovalbumin,lecithin,albuminandmuscleproteininmeat,soyproteininsoybeans,gluteninwheat,glutenincorn,etc.

Semi-completeproteincontainsacompleterangeofessentialaminoacids,butsomeaminoacidsareinsufficientinquantityandinappropriateinproportion.Theycanmaintainlifebutcannotpromotegrowthanddevelopment,suchasgliadininwheat.

Incompleteproteincontainsincompletetypesofessentialaminoacids,whichcanneithersustainlifenorpromotegrowthanddevelopment,suchaszeinincorn,glialproteininanimalconnectivetissueandskin,andinpeasLeguminandsoon.

Classificationofdemandsituation

Essentialaminoacids

TheproteininfoodmustbedigestedbythegastrointestinaltractandbrokendownintoaminoacidsbeforeitcanbeabsorbedbythebodyUtilizing,thehumanbody'sneedforproteinisactuallytheneedforaminoacids.Theabsorbedaminoacidscanonlymeettheneedsofthehumanbodyintermsofquantityandtype,andthebodycanusethemtosynthesizeitsownprotein.Innutrition,aminoacidsaredividedintotwotypes:essentialaminoacidsandnon-essentialaminoacids.

Essentialaminoacidsrefertoaminoacidsthatthehumanbodycannotsynthesizebyitselforthesynthesisspeedcannotmeettheneedsofthehumanbodyandmustbetakeninfromfood.Foradults,thereare8kindsofsuchaminoacids,includinglysine,methionine,leucine,isoleucine,threonine,valine,tryptophan,andphenylalanine.Forbabies,thereare9types,onemorehistidine.

Non-essentialaminoacids

Non-essentialaminoacidsdonotmeanthatthehumanbodydoesnotneedtheseaminoacids,butthatthehumanbodycansynthesizebyitselforobtainitfromotheraminoacids.Itdoesnotnecessarilyhavetobeingesteddirectlyfromfood.Suchaminoacidsincludeglycine,alanine,serine,asparticacid,glutamicacid(anditsamines),proline,arginine,histidine,tyrosine,andcystine.

Somenon-essentialaminoacidssuchascystineandtyrosinecansavetherequiredamountofmethionineandphenylalanineintheessentialaminoacidsifthesupplyissufficient.

Appearanceclassification

Innutrition,foodproteinisdividedintothreecategoriesaccordingtothetypeandquantityofaminoacidscontainedinfoodprotein:

1.CompleteproteinisoneClasshigh-qualityprotein.Theycontainacompleterangeofessentialaminoacids,insufficientquantities,andinanappropriateratiotoeachother.Thistypeofproteincannotonlymaintainhumanhealth,butalsopromotegrowthanddevelopment.

2.Althoughthesemi-completeproteincontainsacompletevarietyofaminoacids,someoftheaminoacidscannotmeettheneedsofthehumanbody.Theycanmaintainlife,buttheycannotpromotegrowthanddevelopment.

3.Proteinssuchasincompleteproteinscannotprovidealltheessentialaminoacidsneededbythehumanbody.Theycanneitherpromotegrowthnormaintainlife.

Accordingtotheshapeofproteinmolecules,theycanbedividedinto3categories

1.Themolecularshapeofglobularproteinisclosetospherical,andthewatersolubilityisgood.Therearemanytypesandcanperformavarietyofbiologicalfunctions.

2.Fibrousproteinmoleculesarerod-shapedorfibrous,andmostofthemareinsolubleinwater.Theyareimportantstructuralcomponentsoforganismsorprotectorganisms.

3.Membraneproteinsaregenerallyfoldedintoanearlysphericalshapeandinsertedintothebiomembrane,andsomeofthemareboundtothesurfaceofthebiomembranethroughnon-covalentbondsorcovalentbonds.Mostofthefunctionsofbiologicalmembranesareachievedthroughmembraneproteins.

Structuraltype

Fibrousprotein:amajortypeofwater-insolubleprotein,usuallycontainingpolypeptidechainswiththesamesecondarystructure.Manyfibrousproteinsaretightlybound.Andtoprovidemechanicalstrengthforindividualcellsortheentireorganism,playingaprotectiveorstructuralrole.

Globularprotein:Atypeofproteinthatiscompact,approximatelyspherical,andcontainstightlyfoldedpolypeptidechains,manyofwhicharesolubleinwater.Thetypicalglobulincontainsdepressionsorfissuresthatcanspecificallyrecognizeothercompounds.

Keratin:Aproteinthatisinsolubleinwaterandplaysaprotectiveorstructuralrole.Itiscomposedofparallelpolypeptidechainsinα-helixorβ-sheetconformation.

Collagen(protein)(collagen):Itisthemostabundantproteininanimalconnectivetissue.Itiscomposedofprocollagenmolecules.Procollagenisaproteinwitharight-handedsupercoilstructure.Eachprocollagenmoleculeisformedbyright-handedrotationofapolypeptidechainwith3specialleft-handedhelixes(pitch0.95nm,eachcirclecontains3.3residues).

Chaperone:Itformsacomplexwithanewlysynthesizedpolypeptidechainandassistsittofoldcorrectlyintoaproteinwithbiologicalfunctionalorientation.Thechaperoneproteincanpreventtheformationofincorrectlyfoldedintermediatesandtheincorrectaggregationofunassembledproteinsubunits,assistinthetransmembranetransportofpolypeptidechainsandtheassemblyanddisassemblyoflargemulti-subunitproteins.

Myoglobin(myoglobin):isabindingproteincomposedofapeptidechainandahemeprostheticgroup.Itisaproteinthatstoresoxygeninthemuscle.Itsoxygensaturationcurveishyperbolic.

Hemoglobin(hemoglobin):isabindingproteincomposedof4subunitscontaininghemeprostheticgroups.Hemoglobinisresponsiblefortransportingoxygenfromthelungstoperipheraltissues,anditsoxygensaturationcurveisS-shaped.

Proteindenaturation(denaturation):Thedestructionofthenaturalconformationofbiologicalmacromoleculesleadstothelossoftheirbiologicalactivity.Whentheproteinisexposedtolight,heat,organicsolventsandsomedenaturants,thesecondarybondsaredestroyed,resultinginthedestructionofthenaturalconformationandthelossofthebiologicalactivityoftheprotein.

Renaturation:Undercertainconditions,thephenomenonthatdenaturedbiologicalmacromoleculesreturntoabiologicallyactivenaturalconformation.

Allostericeffect:Alsoknownasallostericeffect,itisthephenomenonthatthebindingofoligomericproteinandligandchangestheconformationoftheprotein,leadingtothechangeofthebiologicalactivityoftheprotein.

Thestructureoftheproteinthathelpscancercells

Whencancercellsproliferaterapidly,theyseemtoneedthehelpofaproteincalledsurvivin.Accordingtoreportsbysomeresearchers,survivinproteinsareunexpectedlycombinedinpairs-thisdiscoveryislikelytoprovideanewmechanismforthedesignofanti-cancerdrugs.

Inordertofindoutwhatthesurvivinproteindoes,JosephNoel,astructuralbiologistinCalifornia,USA,andhiscolleaguestooktheleadincarefullyobservingitsthree-dimensionalstructure.TheyirradiatedX-raysontheproteincrystalsandmeasuredthedeflectionangleoftheX-rays,whichallowedtheresearcherstocalculatethepositionofeachatomintheprotein.Theresultstheyobtainedpointedoutthatsurvivinproteinformsakindofjunction,whichisnotformedbyotherinhibitorsofapoptosis.TheseresearchersreportedintheJulyissueof"NatureStructuralBiology"thatapartofthesurvivinmoleculeunexpectedlyjoinedwiththecorrespondingpartofanothersurvivinmoleculetoformadimercalledadimer.Proteinpair.Researchersspeculatethatthesedimersofsurvivinproteinsmaymaintainkeymolecularstructuresduringcelldivision.Ifthisproteinmustbepairedinordertofunction,thenusingasmallmoleculetoseparatethemmaybeabletofightcancer.

BiochemistGuySalvesensaidthatmasteringthestructureofthesurvivinprotein"doesnotclarifythedoubtabouthowitpreventscellsuicide."Buthesaidthatthefactthattheseproteinspairupisreallysurprising,"It'salmosthardtofindunimportantdimerizationregions."Healsoagreedthattheinterfacebetweenthetwoproteinswouldbeagoodtargetforanti-cancerdrugstofocuson.

Source

Themainsourcesofproteinaremeat,eggs,milk,andlegumes.Generallyspeaking,proteinfromanimalsisofhighqualityandcontainssufficientessentialAminoacids.Thereareabout8essentialaminoacids,whichcannotbesynthesizedbythehumanbody.Theymustbeingestedfromfood.Ifthereisinsufficientstockofanessentialaminoacidinthebody,sufficientproteincannotbesynthesizedforusebyvarioustissuesofthebody,andotherexcessproteinswillalsobemetabolizedbythebody.It’swasted,soit’simportanttoensureadequateintakeofessentialaminoacids.Plant-basedproteinusuallyhasinsufficientcontentof1-2kindsofessentialaminoacids,sovegetariansneedtoconsumeavarietyoffoodsandobtainenoughessentialaminoacidsfromvariouscombinations.Apieceofcookedmeatthesizeofaplayingcardcontainsabout30-35gramsofprotein,alargecupofmilkcontainsabout8-10grams,andahalfcupofvariousbeanscontainsabout6-8grams.Soeatingapieceofmeatthesizeofapokercard,drinkingtwocupsofmilk,somebeans,plusasmallamountofvegetables,fruits,andrice,youcangetabout60-70gramsofprotein,whichisenoughforalong-distancerunnerweighing60kg.need.Ifyourdemandisrelativelylarge,youcandrinkanextraglassofmilk,oreatmoremeat,togetenoughprotein.

Consumption

Proteinfoodisanimportantnutrientforthehumanbody,andensuringthesupplyofhigh-qualityproteinisanimportantissuerelatedtohealth.Howtochooseproteiniseconomicalandnutritious??

Firstofall,wemustensurethatthereissufficientquantityandqualityofproteinfood.Accordingtoresearchbynutritionists,anadultneedstoupdatemorethan300gofproteineverydaythroughmetabolism,ofwhich3/4arederivedfromaminoacidsproducedinthebody'smetabolism.Thereuseoftheseaminoacidsgreatlyreducestheamountofproteinthatneedstobesupplemented.Generallyspeaking,anadult'sdailyintakeof60gto80gofproteincanbasicallymeettheneeds.

Secondly,areasonablecombinationofvariousfoodsisaneffectivemethodthatiseconomicalandcaneffectivelyincreasethenutritionalvalueofprotein.Itisbesttohaveone-thirdoftheproteinconsumeddailyfromanimalprotein,andtwo-thirdsfromplantprotein.Thepeopleofourcountryhavethehabitofeatingmixedfoods.Mixingseveralkindsofproteinswithlownutritionalvalue.Theaminoacidsinthemcomplementeachother,whichcansignificantlyincreasethenutritionalvalue.Forexample,cerealproteincontainslesslysineandmoremethionine.Beanproteincontainsmorelysineandlessmethionine.Whenthesetwotypesofproteinaremixed,theessentialaminoacidscomplementeachother,closetotheneedsofthehumanbody,andthenutritionalvalueisgreatlyimproved.

Third,everymealmusthaveacertainqualityandquantityofprotein.Thehumanbodydoesnotsetupastoragewarehouseforprotein.Ifyoueattoomuchproteinatatime,itwillinevitablycausewaste.Onthecontrary,whenthereisinsufficientproteininfood,youngpeoplewillbestunted,andadultswillfeelfatigue,weightloss,anddiseaseresistanceweakened.

Fourth,eatingproteinmustbebasedonsufficientcaloriesupply.Ifthecaloriesupplyisinsufficient,thebodywillconsumeproteininfoodforenergy.Eachgramofproteinprovides18kJofcalorieswhenoxidizedinthebody,whichisequivalenttoglucose.Usingproteinasanenergysourceisawaste,anditisanoverkill.

Theproteinintakemaybeexcessive,andtheproteincontentrequiredtomaintainhealthvariesfrompersontoperson.

Theaveragehealthyadultmaleorfemaleneedsapproximately0.8gramsofproteinperkilogram(2.2pounds)ofbodyweight.

Relatedresearch

Extendlifespan

Accordingtoforeignmediareports,agroundbreakingstudymayhelptheelderlylivelongerandmaintainhealthkey.AmericanresearchershavediscoveredaproteincalledSIRT1.Itcannotonlyextendthelifeofmice,butalsodelaytheageofonsetrelatedtohealth.Inaddition,italsoimprovestheoverallhealthofmice,lowerscholesterollevels,andevenpreventsdiabetes.Theresearcherssaidthatalthoughthisstudywasconductedonmice,itwilleventuallybeappliedtohumansoneday.

TheresearchteamledbyDr.RaphaelDeCabooftheNationalInstituteofAgingoftheNationalInstitutesofHealthtestedtheeffectofSIRT1720,asmallmoleculethatactivatesSIRT1,onthehealthandlifespanofmice.Decabsaid:"WehaveverifiedforthefirsttimethattheartificialSIRT1activatornotonlyprolongsthelifespanofratsfedonstandardfood,butalsoimprovestheirhealthspan.Thisshowsthatwemaydeveloptoreducetheburdenofage-relatedmetabolicdiseasesandchronicdiseases.Themolecules.”TheseresearchersalsofoundthatSRT1720prolongedtheaveragelifespanofmiceby8.8%.

SRT1720supplementsalsoreducebodyweightandbodyfatpercentage,andimprovethemusclefunctionandexercisecoordinationabilityofmicethroughoutthelife.

ScientistshavefoundthatSRT1720supplementslowertotalcholesterolandlow-densitylipoproteincholesterollevelsthathelpfightheartdisease,andimproveinsulinsensitivitythatmayhelppreventdiabetes.

SIRT1anditssisterproteinSIRT2areknowntoscientistsastheyplayanimportantroleinthemetabolismofalargenumberofspecies.TheyarealsoinvolvedinDNArepairandgeneregulation,andmayhelppreventdiabetes,heartdiseaseandcancer.Miceareprovidedwiththissupplementandstandarddietat6monthsofageandotherlifestages.Butexpertswarnthatthisresearchisstillinaveryearlystage,andnorelevantexperimentshavebeenconductedonhumans.

Relateddisciplines

1982AmericanS.B.PrusinerdiscoveredtheproteinfactorPrion,updatedtheconceptofmedicalinfection,andwontheNobelPrizeinPhysiologyandMedicinein1997.

Oneofthemostamazingdiscoveriesofthe20thcenturyisthattheactiveandinactivestatesofmanyproteinscanbeconvertedintoeachotherunderapreciselycontrolledsolutioncondition(forexample,bydialysistoremovetheinactivechemicalsubstance),Theinactivatedproteincanbeconvertedintoanactiveform.Howtorestoreproteinstotheiractivestateisamajorresearchareaof​​biochemistry,calledproteinfolding.

ProteinsynthesisistotranscribetheinformationhiddeninDNAintomRNAthroughtheactionofenzymesinthecell,andthenthecorrespondingaminoacidsaretransportedtoribosebytRNAaccordingtotheprincipleofcodon-anticodonpairingInthebody,theyarearrangedinstringsinorderaccordingtotheencodingofthemRNAtoformapolypeptidechain,whichisthenfoldedandtwistedintoaprotein.Proteinisthebasicmacromoleculeoflife.Itcanberegardedasabrickofalivingbody.

Throughgeneticengineering,researcherscanchangethesequenceandtherebychangethestructureoftheprotein,targetsubstance,regulatorysensitivityandotherproperties.Thegenesequencesofdifferentproteinscanbespliced​​togethertoproducetwo"absurd"proteinswithproteinproperties.Thisformofpatchinghasbecomeamajortoolforcellbiologiststochangeorprobecellfunctions.Inaddition,anotherattemptinthefieldofproteinresearchistocreateaproteinwithbrand-newpropertiesorfunctions.Thisfieldiscalledproteinengineering.

Foodcontent

Foodswithalotofproteininclude:livestockmilk,suchasmilk,goatmilk,horsemilk,etc.;livestockmeat,suchascattle,sheep,pork,etc.;poultry,Suchaschicken,duck,goose,quail,etc.;eggs,suchaseggs,duckeggs,quaileggs,fish,shrimp,crabs,etc.;andsoybeans,includingsoybeans,greenbeansandblackbeans,amongwhichsoybeanshavethehighestnutritionalvalue,Itisahigh-qualitysourceofproteinininfantfood;inaddition,driedfruitssuchassesame,melonseeds,walnuts,almonds,pinenutsandotherdriedfruitshavehigherproteincontent.Sincethecontentofaminoacidsinvariousfoods,thetypesofaminoacidscontainedaredifferent,andthecontentofothernutrients(fat,sugar,minerals,vitamins,etc.)arealsodifferent,theabovefoodsareallavailablewhenaddingcomplementaryfoodstobabiesIfyouchoose,youcanalsoprovidechildrenwithhigh-proteinfoodsaccordingtolocalconditions.

Proteinfoodsareexpensive.Parentscanuseseveralcheapfoodstomixtogethertoincreasetheutilizationrateofproteininthebody.Forexample,thebiologicalvalueofsimplyeatingcornis60%andwheatis67.%,soybeansare64%.Ifthesethreefoodsaremixedinproportionandeaten,theproteinutilizationratecanreach77%.Aubiquitousbiologicalmacromoleculecomposedofaminoacids.Itisthemostbasicsubstanceoflivingorganismsaswellasnucleicacid,anditisresponsibleforvariousextremelyimportantfunctionsintheprocessoflifeactivities.Thebasicstructuralunitofproteinisaminoacid,andthereare20kindsofaminoacidsappearinginprotein.Aminoacidsareconnectedtoeachotherbypeptidebondstoformapeptidechain.

AbriefhistoryIn1820,H.Braconodiscoveredglycineandleucine,whichweretheaminoacidsthatwereinitiallyidentifiedasproteincomponents,andotheraminoacidsweresubsequentlydiscovered.Bytheendofthe19thcentury,itwasclearthatproteinwasmainlycomposedofaclassoffairlysimpleorganicmolecules-aminoacids.In1902,E.FischerandF.Hofmeisterindependentlyclarifiedthatthechemicalbondsthatconnectaminoacidsinproteinmoleculesarepeptidebonds;in1907,E.Fischersucceededinchemicallyconnecting18aminoacidssynthesizedpeptidesforthefirsttime,thusestablishingthepeptidetheoryasthebasisofproteinchemicalstructure.Theknowledgeoftheprecisethree-dimensionalstructureofproteinsmainlycomesfromtheX-raydiffractionanalysisofproteincrystals.In1960,JCKendrewusedX-raydiffractionanalysistechnologytodeterminethecrystalstructureofmyoglobinforthefirsttime.Thiswasthefirstthree-dimensionalstructuretobeelucidated.Protein.Chinesescientistscompletelysynthesizedcrystallinebovineinsulinbychemicalsynthesisin1965,realizingtheartificialsynthesisofproteinforthefirsttime;from1969to1973,thecrystalstructureofporcineinsulinwasdeterminedat2.5angstromsand1.8angstromsresolution.,Thisisthefirstthree-dimensionalstructureofaproteinclarifiedbyChina.

Activity

Aftertheproteinmoleculeisaffectedbysomeexternalphysicalandchemicalfactors,althoughthepeptidechainofthemoleculeisnotcleaved,itsnaturalthree-dimensionalstructureischangedanddestroyed.Thisleadstothelossofproteinbiologicalactivityandotherchangesinphysicalandchemicalproperties.Thisphenomenoniscalledproteindenaturation.Asearlyas1931,ChinesebiochemistWuXianputforwardthecorrecttheoryofdenaturationforthefirsttime.Themainfactorsthatcauseproteindenaturationare:①Temperature.②pH.③Organicsolvents.④Ureaandguanidinehydrochloride.Thisisthemostwidelyusedproteindenaturationreagent.⑤Detergentsandaromaticringcompounds.

Thedenaturationofproteinisoftenaccompaniedbythefollowingphenomena:①Lossofbiologicalactivity.Thisisthemostimportantfeatureofproteindenaturation.②Changesinchemicalproperties.③Changesinphysicalproperties.Afterthedenaturationfactorisremoved,thedenaturedproteinmoleculecanreturntoitsnaturalconformationbeforedenaturation.Thisphenomenoniscalledproteinrenaturation.Therenaturationofproteinincludescompleterenaturation,basicrenaturationorpartialrenaturation.Onlyafewproteinscanfullyrenatureafterseveredenaturation.Thestudyofproteindenaturationandrenaturationisveryimportanttounderstandthefoldingprocessofproteinmoleculesinvivoandinvitro.Mainlythroughthestudyofproteindenaturationandrenaturation,thespontaneityofproteinfoldinghasbeenaffirmed,andthecharacteristicthree-dimensionalstructureofproteinmoleculesisonlydeterminedbyitsaminoacidsequence.Whentheactiveproteinmoleculeisjustsynthesizedintheorganism,itoftendoesnotshowactivity,thatis,itdoesnothavethespecificbiologicalfunctionofthisprotein.Inorderforaproteintoexhibititsbiologicalactivity,averycommonphenomenonisthatthepeptidechainofaproteinmoleculemustbebrokeninaspecificwayduringsomebiochemicalprocesses.Theactivationofproteinisawayofbiologicalregulation,andthiskindofphenomenoniswidespreadinvariousimportantlifeactivities.

Manyproteinsarecomposedofsubunits.Whenthistypeofproteincompletesitsbiologicalfunctions,theregulationofefficiencyandreactionspeeddependstoalargeextentontherelationshipbetweenthesubunits.Itisafairlycommonphenomenonthatsubunitsparticipateintheregulationofproteinfunctions,especiallyinregulatingthecatalyticfunctionofenzymes.Someenzymeshaveallostericsitesthatdonotoverlapwiththeactivesite.Thecombinationoftheallostericsiteandtheallostericligandcauseschangesinthethree-dimensionalstructureoftheenzymemolecule,resultinginchangesinthethree-dimensionalstructureoftheactivesite.ThischangemayincreaseormayInactivatethecatalyticabilityoftheenzyme.Suchenzymesarecalledallostericenzymes.Knownallostericenzymeshavetwoormoresubunitsinstructure.

Function

Proteinhasmanyfunctionsintheorganism.

CatalyticfunctionProteinswithcatalyticfunctionarecalledenzymes,andallthechemicalreactionsinthemetabolismoforganismsarecatalyzedbyenzymes.

Motionfunctionsfromthelowestbacterialflagellamovementtothemusclecontractionofhigheranimalsareachievedthroughprotein.Musclerelaxationandcontractionaremainlyaccomplishedbytheslidingofthickfilamentswithmyosinasthemaincomponentandfinefilamentswithactinasthemaincomponent.

TransportfunctionIntheprocessoflifeactivities,thetransportationofmanysmallmoleculesandionsiscompletedbyavarietyofspecializedproteins.Forexample,plasmaalbumintransportssmallmoleculesintheblood,andhemoglobininredbloodcellstransportsoxygenandcarbondioxide.

MechanicalsupportandprotectionThetissueswithmechanicalsupportfunctionsofhigheranimals,suchasbone,connectivetissue,andcoveringandprotectinghair,skin,nailsandothertissuesaremainlycomposedofcollagen,keratin,elastin,etc.composition.

Inordertomaintaintheirownsurvival,immuneanddefenseorganismshavevarioustypesofdefensemethods,manyofwhichareexecutedbyproteins.Forexample,antibodiesareaclassofhighlyspecificproteinsthatcanrecognizeandbindforeignsubstancesthatinvadeorganisms,suchasforeignproteins,viruses,andbacteria,andcanceltheirharmfuleffects.

RegulatoryfunctionInthemaintenanceofthenormallifeactivitiesoforganisms,theregulationofmetabolicfunctions,thecontrolofgrowthanddifferentiation,theregulationofreproductivefunctionsandthecontinuationofspecies,etc.,polypeptideandproteinhormonesplayarolePlaysanextremelyimportantrole.Inaddition,thereareproteinsthatreceiveandtransmitregulatoryinformation,suchasreceptorproteinsforvarioushormones.

Development

Asabiologicalmacromoleculethatplaysanimportantroleinlifeactivities,proteiniscloselyrelatedtoallmajorresearchtopicsthatuncoverthemysteriesoflife.Proteinisthemainfoodingredientforhumansandotheranimals,andahigh-proteindietisoneoftheimportantsignsoftheimprovementofpeople'slivingstandards.Manypureproteinpreparationsarealsoeffectivedrugs,suchasinsulin,humangammaglobulinandsomeenzymepreparations.Inclinicaltesting,thedeterminationoftheactivityofrelatedenzymesandthechangesofcertainproteinscanbeusedasindicatorsfortheclinicaldiagnosisofsomediseases.Forexample,theidentificationoflactatedehydrogenaseisoenzymescanbeusedasindicatorsofmyocardialinfarction,andtheelevationofalpha-fetoproteincanbeAsanindicatorofearlylivercancerlesions,etc.Inindustrialproduction,certainproteinsareimportantrawmaterialsforthefoodindustryandlightindustry.Forexample,woolandsilkarebothproteins,andleatherisprocessedcollagen.Afterapplyingvariousenzymepreparationsinindustrialsectorssuchastanning,pharmacy,andsilkreeling,productionefficiencyandproductqualitycanbeimproved.Theimportanceofproteininagriculture,animalhusbandry,andaquacultureisalsoobvious.

Proteincanbeusedasareagentforscreeningcompoundsorsaltsthereofthatcanpromoteorinhibittheactivityoftheproteinofthepresentinvention.Furthermore,thecompoundoritssaltandtheneutralizingantibodythatinhibitstheactivityoftheproteinofthepresentinventioncanbeusedasdrugsforthetreatmentorpreventionofbronchialasthma,chronicobstructivepulmonarydisease,andthelike.

Proteinplaysaveryimportantroleinthelifeactivitiesofcellsandorganisms.Thestructureandshapeoflivingthingsarerelatedtoproteins.Proteinisalsoinvolvedintheregulationofgeneexpression,aswellasmanylifeactivitiessuchasredox,electrontransfer,neurotransmission,learningandmemoryincells.Theenzymesthatcatalyzevariousbiochemicalreactionsincellsandorganismsaremainlyproteins.Manyimportanthormones,suchasinsulinandthymushormone,arealsoproteins.Inaddition,avarietyofproteins,suchastheproteininplantseeds(beans,peanuts,wheat,etc.),animalprotein,cheese,etc.,areproteinsforthenutritionalgrowthoforganisms.Someproteins,suchassnakevenomandbeevenom,areweaponsofanimalattackanddefense.

Proteinaccountsfor20%ofthehumanbody,whichisthelargestproportionofthebody.Bile,excepturine,areallproteinsynthesis.Onlywhenproteinissufficientcanthemetabolismbenormal.Justlikebuildingahouse,themainrawmaterialforbuildingthebodyisprotein.

1.Proteinisthebasicmaterialfortheconstructionofnewtissues,andistherawmaterialforenzymeandhormonesynthesis;itmaintainsthebalanceofpotassiumandsodium;andeliminatesedema.

2.Itisthecomponentsofsyntheticantibodies:whitebloodcells,Tlymphocytes,interferons,etc.,whichimproveimmunity.

3.Providesomeenergy.

4.Lowerbloodpressure,bufferanemia,itisthecarrierofredbloodcells.

5.Formthebody'scollagen.Thevitreousoftheeyeballandrhodopsinhavecollagen.

7.Thepowersourceforbraincelldivisionisprotein;thecerebrospinalfluidissynthesizedbyprotein;memoryisdecreased

8.Sexualdysfunction

9.Liver:hematopoiesisFunction;synthesisofhormones,enzymes;detoxification.Lackofproteinandunhealthylivercells.Withagoodliver,one’shealthisguaranteed.

10.Heart---pumporgan.Lackofproteinwillcausecoldhandsandfeet;hypoxia;myocardialhypoxiacancauseheartfailure-death.

11.Spleenandstomach:digestfoodeveryday,digestiveenzymesaresynthesizedbyprotein.Lackwillcauseinsufficientgastricmotility,indigestion,andhiccups.Stomachulcer,gastritis;excessivegastricacid,irritatingtheulcersurface,youwillfeelpain,proteinonlyhasthefunctionofrepairingregeneratedcells.Thereareligamentsonthedigestivewall,thelackofproteinwillloosen,theinternalorganswilldroop,andtheuterineorganswillshift.

12.Limbs:Olderpeople,oldlegs,lackofproteinandmuscleatrophy;bonetoughnessisreduced,easytofracture

13.Antibodieswillbereduced,easytocatchcolds,andfever.

Mainresearch

History

Inthe18thcentury,AntonioFrançois(AntoineFourcroy)andotherresearchersdiscoveredthatproteinsareauniqueclassForbiologicalmolecules,theyfoundthattreatingsomemoleculeswithacidcanmakethemcoagulateorflocculate.Theexamplestheynoticedatthetimewereproteinfromeggwhite,blood,serumalbumin,celluloseandwheatgluten.DutchchemistGerhardusJohannesMulderconductedelementalanalysisongeneralproteinsandfoundthatalmostallproteinshavethesameexperimentalformula.Theuseoftheterm"protein"todescribethistypeofmoleculewasproposedin1838byMulder'scollaboratorJonsBezelius.Mulderthenidentifiedthedegradationproductoftheproteinandfoundthatitcontainedleucine,whichisanaminoacid,andgotits(veryclosetothecorrectvalue)molecularweightof131Da.

Forearlybiochemists,thedifficultyofstudyingproteinsisthatitisdifficulttopurifylargeamountsofproteinsforresearch.Therefore,earlyresearchworkfocusedonproteinsthatcanbeeasilypurified,suchasblood,eggwhite,proteinsinvarioustoxins,anddigestiveandmetabolicenzymes(obtainedfromslaughterhouses).Inthelate1950s,ArmourHotDogCo.purifiedribonucleaseAfromonekilogramofpurebovinepancreasandprovidedittoscientistsallovertheworldforfree.Scientistscanbuymoreandmoretypesofpureproteinsfrombiologicalcompanies.

ThefamouschemistLinusPaulingsuccessfullypredictedtheregularproteinsecondarystructurebasedonhydrogenbonds,andthisideawasfirstproposedbyWilliamAstburyin1933.Subsequently,WalterKauzmansummarizedhisresearchresultsondenaturationandthepreviousresearchworkofKajLinderstrom-Lang,andproposedthatproteinfoldingismediatedbyhydrophobicinteractions.In1949,FrederickSangercorrectlydeterminedtheaminoacidsequenceofinsulinforthefirsttimeandverifiedthattheproteinisalinear(nobifurcationorotherform)polymerformedbyaminoacids.AtomicresolutionproteinstructurewasfirstanalyzedbyX-raycrystallographyinthe1960s;inthe1980s,NMRwasalsoappliedtotheanalysisofproteinstructure,andcryo-electronmicroscopywaswidelyusedtoanalyzethestructureofsuper-largemolecularcomplexes..AsofFebruary2008,therearecloseto50,000atomicresolutioncoordinatesofthethree-dimensionalstructureofproteinsandrelatedcomplexesintheproteindatabase.

Researchmethods

Proteinsarethemoststudiedtypeofbiomolecules,andtheirresearchincludes"invivo"and"invitro".Invitrostudiesaremostlyappliedtopurifiedproteins,placingtheminacontrollableenvironmentinordertoobtaintheirfunctionalinformation;forexample,studiesrelatedtoenzymekineticscanrevealthechemicalmechanismofenzyme-catalyzedreactionsandtheirinteractionwithdifferentsubstratemolecules.Relativeaffinitybetween.Invivoresearchexperimentsfocusontheactiveroleofproteinsincellsorentiretissues,soastounderstandwhereproteinsfunctionandthecorrespondingregulatorymechanisms.

Anti-cancereffect

Whencancercellsproliferaterapidly,theyneedthehelpofaproteincalledsurvivin.Thisproteinisencodedandsynthesizedbytheapoptosis-suppressinggeneSurvivin.Itisabundantincancercells,butitisalmostabsentinnormalcells.Thedependenceofcancercellsonsurvivinproteinmakessurvivinanaturaltargetforthemanufactureofnewanticancerdrugs,buttherearestillsomeunsolvedmysteriesonhowtodealwithsurvivinprotein.

Survivinproteinbelongstoaclassofproteinsthatpreventcellsfromdestroyingthemselves(ie,apoptosis).Suchproteinsmainlyinhibittheactionofapoptoticenzymes(caspases)topreventthemfromsendingcellsontheroadtosuicide.Noscientisthaseverobservedtheinteractionbetweensurvivinproteinandapoptoticenzyme.Therearealsoothersignsthatthesurvivinproteinplaysadifferentrole-helpingtopullthecellapartaftercelldivision.

BiochemistGuySalvesenmasteredthestructureofsurvivinprotein"anddidnotclarifythedoubtabouthowitpreventscellsuicide."Thefactthattheseproteinspairupisindeedsurprising,anditisalmostdifficulttofindunimportantdimerizationregions.Theinterfacebetweenthetwoproteinswillbeagoodtargetforanti-cancerdrugstointensivelydealwith.

Omics

Proteomics(Proteomics)wasmentionedbefore1996.Iamafraidthatveryfewpeopleknowit,andsomepeoplearestillskepticalaboutknowingthetwo..However,the2001Sciencemagazinehaslistedproteomicsasoneofthesixresearchhotspots,anditspopularityissecondonlytostemcellresearch.Thelevelofinterestinproteomicsisnowimpressive.

1.Researchsignificanceandbackgroundofproteomicsresearch

WiththeimplementationandadvancementoftheHumanGenomeProject,lifescienceresearchhasenteredthepost-genomeera.Inthisera,themainresearchobjectoflifesciencesisfunctionalgenomics,includingstructuralgenomicsresearchandproteomicresearch.Althoughthegenomesofmultiplespecieshavebeensequenced,thefunctionofmorethanhalfofthegenesinthesegenomesisusuallyunknown.Thestrategiesusedinfunctionalgenomics,suchasgenechip,serialanalysisofgeneexpression(SAGE),etc.,areallconsideredfromtheperspectiveofmRNAinthecell,andthepremiseisthatthelevelofmRNAinthecellreflectstheproteinThelevelofexpression.Butthefactisnotexactlythecase.FromDNAmRNAprotein,therearethreelevelsofregulation,namelytranscriptionalcontrol,translationalcontrol,andpost-translationalcontrol.FromtheperspectiveofmRNA,itactuallyonlyincludestheregulationofthetranscriptionlevel,anddoesnotfullyrepresentthelevelofproteinexpression.ExperimentshavealsoprovedthatthecorrelationbetweenmRNAabundanceandproteinabundanceintissuesisnotgood,especiallyforlow-abundanceproteins,thecorrelationisevenworse.Moreimportantly,complexpost-translationalmodificationsofproteins,subcellularlocalizationormigrationofproteins,andprotein-proteininteractionsarealmostimpossibletojudgefromthemRNAlevel.Undoubtedly,proteinistheexecutorofphysiologicalfunctionsandthedirectmanifestationoflifephenomena.Thestudyofproteinstructureandfunctionwilldirectlyclarifythechangemechanismoflifeunderphysiologicalorpathologicalconditions.Theexistenceoftheproteinitselfandthelawsofitsactivities,suchaspost-translationalmodification,protein-proteininteractionandproteinconformation,stillrelyondirectproteinresearchtosolve.Althoughthevariabilityanddiversityofproteinsandotherspecialpropertiesmakeproteinresearchtechnologyfarmorecomplexanddifficultthannucleicacidtechnology,itisthesecharacteristicsthatparticipateinandaffecttheentirelifeprocess.

2.Strategiesandscopeofproteomicsresearch

Onceproteomicsemerged,thereweretworesearchstrategies.Onecanbecalledthe"exhaustionmethod",thatis,theuseofhigh-throughputproteomicsresearchtechniquestoanalyzeasmanyaspossibleorevenclosetoallproteinsintheorganism.Thisviewlooksatproteomicsfromalarge-scaleandsystematicperspective.Itisalsomoreinlinewiththeessenceofproteomics.However,becauseproteinexpressionchangescontinuouslywithspaceandtime,itisanelusivegoaltoanalyzealltheproteinsintheorganism.Anotherstrategycanbecalled"functionalmethod",thatis,tostudythechangesincellproteincompositionindifferentperiods,suchasthedifferentialexpressionofproteinsindifferentenvironments,withthemaingoalofdiscoveringdifferentproteintypes.Thisviewismoreinclinedtouseproteomicsasameansandmethodtostudylifephenomena.

Theresearchscopeofearlyproteomicsmainlyreferstotheexpressionprofileofproteins.Withthedevelopmentofthediscipline,theresearchscopeofproteomicsisconstantlyimprovingandexpanding.Thestudyofproteinpost-translationalmodificationhasbecomeanimportantpartandahugechallengeintheresearchofproteomics.Thestudyofprotein-proteininteractionhasalsobeenincludedintheresearchcategoryofproteomics.Theanalysisofproteinhigh-levelstructureistraditionalstructuralbiology.Althoughsomepeopletrytoincludeitinthescopeofproteomicsresearch,itisstillunique.

3.Proteomicsresearchtechnology

Itcanbesaidthatthedevelopmentofproteomicsisnotonlydrivenbytechnologybutalsolimitedbytechnology.Thesuccessofproteomicsresearchdependslargelyonthelevelofitstechnicalmethods.Proteinresearchtechnologyisfarmorecomplicatedanddifficultthangenetechnology.Notonlyarethetypesofaminoacidresiduesfarmorethannucleotideresidues(20/4),butproteinshavecomplexpost-translationalmodifications,suchasphosphorylationandglycosylation,whichbringmanydifficultiestotheseparationandanalysisofproteins.Inaddition,itisnoteasytoperforminvitroamplificationandpurificationofproteinsthroughexpressionvectors,makingitdifficulttopreparelargeamountsofproteins.Theriseofproteomicshasbroughtnewdemandsandchallengestotechnology.Theresearchofproteomicsisessentiallythelarge-scaleparallelseparationandanalysisofproteinsatthecellularlevel,oftenprocessingthousandsofproteinsatthesametime.Therefore,thedevelopmentofahigh-throughput,high-sensitivity,andhigh-accuracyresearchtechnologyplatformisthemaintaskinproteomicsresearchforquitesometime.Thetechnicalfoundationanddevelopmenttrendoftheinternationalproteomicsresearchtechnologyplatformareasfollows:

3.2Sampleseparationandanalysisinproteomicsresearch

UsingtheisoelectricpointandMolecularweightisaveryeffectivemethodtodistinguishvariousproteinsbytwo-dimensionalgelelectrophoresis.Itplaysakeyroleinproteomicseparationtechnology.Howtoimprovetheseparationcapacity,sensitivityandresolutionoftwo-dimensionalgelelectrophoresisandtheaccuratedetectionofdifferentialexpressionofproteinsarekeyissuesinthedevelopmentoftwo-dimensionalgelelectrophoresistechnology.ThemainforeigntrendsincludetheuseofnarrowpHgradientgelseparationinfirst-dimensionalelectrophoresisandthedevelopmentofhigh-sensitivityproteinstainingtechniquescombinedwithtwo-dimensionalgelelectrophoresis,suchasnewfluorescentstainingtechniques.

Massspectrometrytechnologyisthefastestgrowing,mostdynamicandpotentialtechnologyinproteomicsresearch.Itdeterminesthetypeofproteinbymeasuringthequalityoftheprotein.Thecoretechnologyofcurrentproteomicsresearchistwo-dimensionalgelelectrophoresis-massspectrometrytechnology,whichseparatesproteinsbytwo-dimensionalgelelectrophoresis,andthenusesmassspectrometrytoidentifytheproteinsonebyone.Forproteinidentification,highthroughput,highsensitivityandhighprecisionarethethreekeyindicators.Thegeneralmassspectrometrytechnologyisdifficulttointegratethethree,andthedevelopedmassspectrometrytechnologycanmeettheabovethreerequirementsatthesametime,soastorealizetheaccurateandlarge-scaleidentificationofproteins.

Thenitrogencontentofproteinisrelativelyconstant,withanaverageofabout16%.

Therelationshipwithheight

Accordingtoreports,duringtheSecondWorldWar,thesupplyofanimalfoodinJapanwasinsufficient,andeachpersononlysupplied2kilogramsofmeat,12.5kilogramsofmilkandmilkeachyear.Products,2.5kgofeggs.Atthattime,theaverageheightof12-year-oldstudentswasonly137.8cm.Afterthewar,Japan'seconomydevelopedrapidly,people'slivesimproved,andanimalfoodsincreased.Eachpersonconsumed13kilogramsofmeat,25kilogramsofmilkanddairyproducts,and15kilogramsofeggseachyear.Accordingtoasurveyin1970,theheightofa12-year-oldteenager(JuvenileFood)hasreached147.1cm,anaverageheightincreaseof9.3cm.Fromthisexample,wecanseetheeffectofproteinfood(proteinfood)ontheincreaseofchildren(children'sfood).

Proteinisthemaincompoundthatconstitutesalllife,thematerialbasisandthefirstelementoflife,anditoccupiestheprimarypositioninnutrients.Childrenandinfantscannotincreasetheirheightwithoutprotein.Thebonesandothertissuesofthehumanbodyarecomposedofprotein.Inallthechemicalreactionsofmetabolisminthebody,thecatalysisofenzymesisinseparable,andallenzymesaremadeofprotein.Thevarioushormonesthatplayaroleinthegrowthofadolescentsarealsoproteinsandtheirderivatives.Inaddition,bonemineralizationbinder,osteocalcin,alkalinephosphatase,humanbone-specificgrowthfactorandothersubstancesinvolvedintheprocessesofbonecelldifferentiation,boneformation,bonereconstructionandrenewalarealsocomposedofproteins.Therefore,proteinisthemostimportantcompoundinhumangrowthanddevelopment,andanimportantrawmaterialforgrowth.

Fat-solublevitamins(vitaminfood),iron(ironfood),calcium,phosphorusandotherinorganicsaltsandsometraceelements(traceelementfood)necessaryforthegrowthanddevelopmentofinfantsandyoungchildren(foodforinfantsandyoungchildren)andchildren),canalsobeobtainedinproteinfoodsatthesametime.Therefore,somechildrenandadolescentsonlyliketoeatvegetarianfood(vegetarianfood)andareafraidofeatingmeatdishessuchaschicken,fish,meat,eggs,orreluctantlyeatalittleunderthesupervisionoftheirparents.ThispracticeisundesirableandwillinevitablyleadtoTheheightisaffectedbylackofprotein.

Thecorrectdietaryprincipleistohaveavarietyoffoods,matchthethickness,adheretograins,beans,andvegetables,andincreasetheamountofmeat,fish,eggs,andmilkappropriatelytosupplementadequatenutritionforphysicaldevelopment.Therawmaterialsthatensuretheheightincrease,promotetheheightofthebody.

Supplementarynotes

Theproteinfoodsourcesofproteincanbedividedintotwocategories:plant-basedproteinandanimal-basedprotein.Amongplantproteins,cerealscontainabout10%protein,whichisnothigh,butbecauseitisthestaplefoodofpeople,itisstillthemainsourceofdietaryprotein.Beansarerichinprotein,especiallysoybeanswhichcontain36%-40%ofprotein.Theaminoacidcompositionisalsoreasonable,andtheutilizationrateinthebodyishigh.Itisaverygoodsourceofproteininplantproteins.

Eggscontain11%~14%proteinandareanimportantsourceofhigh-qualityprotein.Milk(milk)generallycontains3.0%~3.5%protein,whichisthebestsourceofproteinforinfantsandyoungchildren.Proteiniscomposedofaminoacids.Amongthe22essentialaminoacidsforthehumanbody,9kindsofaminoacids(aminoacidfoods)cannotbesynthesizedbythehumanbodyorininsufficientsynthesis,andtheymustbeobtainedthroughdiet.

Meatincludesthemusclesofpoultry,livestockandfish.Freshmusclecontains15%~22%protein.Thenutritionalvalueofmuscleproteinisbetterthanthatofplantprotein.Itisanimportantsourceofhumanprotein.

Themainsourceofproteinisdividedintoanimalproteinandplantprotein.Generallyspeaking,thenutritionalvalueofanimalproteinishigherthanthatofplantprotein.Calculatedbyproteinper500grams,foodsrichinproteininclude:

①Meatproducts:84.5gramsofpork,100.5gramsofbeef,100.5gramsofliver;

②EggsTypes:63.5gramsofeggs,63gramsofduckeggs;

③Fishandshrimp:88gramsofcarp,83gramsofgrasscarp,80gramsofseashrimp;

④Ricenoodles:60.5gramsofwheatflour,50gramsofbarley,42.5gramsofcorn;

⑤Beans:11gramsofmungbeans,108.5gramsofredbeans,249gramsofblackbeans;

⑥Vegetables:70gramsofdaylily,41kelpgram.Soyproteinhasbetternutrition,anditishigh-qualityproteinwithanimalprotein.

Calculatetherequiredamount

Therequiredamountofproteinmayvaryduetovariousfactorssuchashealthstatus,age,weight,etc.Peoplewhoaretallerandolderoryoungerrequiremoreprotein.

Thefollowingfiguresaretheindexofproteinrequiredbypeopleofdifferentages:

Age1-34-67-1011-1415-1819andabove

Index1.801.491.210.990.880.79

Thecalculationmethodis:

Firstfindoutyourownagegroupindex;thenmultiplythisindexbyyourownweight(kg);Theansweristhenumberofgramsofproteinyouneedinaday.

Forexample:weight50kg,age33yearsold,itsindexis0.79.

0.79×50=39.5grams.Thisistheamountofproteinneededinaday.

Theaverageproteinrequirementinadayisabout45gramsatleast,whichisabout15gramsforameal.Notethatbreakfastmustbeadequateproteinintake.

Applicabletoallpeoplewhoneedproteinsupplementation.Pregnantandlactatingwomen,urbanwhite-collarworkerswithhighworkpressure,oftenstayinguplatetowork,elderlyparents,youngchildreninthegrowthanddevelopmentperiod,peoplerecoveringfromsurgery,highbloodpressure.

Supplementafterchildbirth

Therearethreepointstopayattentiontotheproteinintakeafterchildbirth:

First,theproteinintakemustbesufficient,becausethenewmotherBreastfeedingrequiresadequateproteinintake

Second,proteinshouldbehigh-quality.Generallyspeaking,fishandshrimpproteinisbetterthanmeat,andwhitemeatisbetterthanredmeat.Trynottoeatmeatthatmaybeartificiallyfedwithhormones.Instead,eatnaturalfoods.

Third,proteinintakeshouldbebalanced,anddon'tjustchooseonefoodtoeat.

少数人乳汁量不够，下奶比较慢，为了有助于下奶，可喝一些加有中药成分的汤类。这有助于母亲身体的恢复调理（子宫收缩、恶露排出），下奶通畅，并可补充营养。

健身人群补充

健身锻炼期间，人体对蛋白质的需求比其他阶段要旺盛得多。粮食类蛋白质含有的赖氨酸较少，如果将其与大豆、肉食、蛋类等含有较多赖氨酸的食物搭配食用，就会相互提高几者间的营养价值。再比如，大豆中含有的蛋氨酸很低，而玉米中蛋氨酸却很高，如果两者之间组合一下，就会产生互补，提高营养价值。

通过上面的实例，在健身锻炼期间调整我们以往的饮食结构，实现食物多样化，粗粮细粮均衡搭配，动物蛋白合理分配到每一餐，适量摄取豆制品，可以很好地提高我们每一餐的营养价值。在这一情况下进行健身锻炼，最终表现出来的结果是健身效果明显提高。