Los ntawm Peptide Cov Ntaub Ntawv 
Lub Plaub Hlis 21, 2025
Tag nrho cov kab lus thiab cov ntaub ntawv ntawm cov khoom lag luam muab rau ntawm lub vev xaib no tsuas yog rau cov ntaub ntawv tshaj tawm kev tshaj tawm thiab cov hom phiaj kev kawm.
Cov khoom muab rau hauv lub vev xaib no yog npaj tshwj xeeb rau kev tshawb fawb hauv vitro. Kev tshawb fawb hauv vitro (Latin: * hauv iav *, lub ntsiab lus hauv iav) yog ua los ntawm tib neeg lub cev. Cov khoom no tsis yog tshuaj, tsis tau txais kev pom zoo los ntawm US Food and Drug Administration (FDA), thiab yuav tsum tsis txhob siv los tiv thaiv, kho, lossis kho txhua yam mob, kab mob, lossis mob. Nws raug txwv nruj raws li txoj cai los qhia cov khoom no rau hauv tib neeg lossis tsiaj lub cev hauv txhua daim ntawv.
Dab tsi yog Peptide Bond
Ib daim ntawv cog lus peptide yog tus yam ntxwv covalent daim ntawv cog lus nyob rau hauv cov protein molecules, tsim los ntawm lub cev qhuav dej condensation cov tshuaj tiv thaiv ntawm α-carboxyl pawg (α-COOH) ntawm ib qho amino acid thiab α-amino pawg (-NH₂) ntawm ib qho amino acid uas nyob ib sab. Nws cov tshuaj lom neeg yog ib daim ntawv cog lus amide. Qhov kev sib txuas no txiav txim siab cov qauv hauv nruab nrab ntawm cov saw hlau polypeptide: cov amino-terminal (N-terminal) thiab carboxyl-terminal (C-terminal) tau txuas nrog los ntawm kev rov ua dua peptide daim ntawv cog lus los tsim cov kab sib txuas. Vim yog qhov tsim ntawm p-π conjugation system ntawm carbonyl carbon (C = O) thiab imino nitrogen (-NH-) nyob rau hauv daim ntawv cog lus peptide, CN daim ntawv cog lus nthuav tawm ib feem ntawm ob daim ntawv cog lus, endowing peptide daim ntawv cog lus dav hlau nrog rigid coplanar nta. Qhov no muab cov txheej txheem tseem ceeb rau kev folding ntawm cov txheej txheem protein ntau dua.
Mechanism ntawm Peptide Bond Biosynthesis
Peptide bond synthesis tshwm sim hauv ribosomes, tso siab rau kev hloov pauv RNA (tRNA) kom nqa cov amino acids. Los ntawm kev sib koom ua ke ntawm anticodons ntawm tRNA nrog codons ntawm messenger RNA (mRNA), amino acids yog nyob rau ntawm P site thiab A site ntawm ribosome. Cov amino pawg ntawm cov amino acid ntawm qhov chaw A tau ua kom lub cev qhuav dej nrog cov carboxyl pawg ntawm cov amino acid ntawm P site, tsim ib qho amide daim ntawv cog lus (-CO-NH-) thiab tso cov dej molecule. Lub ribosome txav raws mRNA, ua rau cov saw peptide txuas ntxiv los ntawm N-terminal mus rau C-terminal. Cov txheej txheem no yog siv los ntawm GTP, nrog rau kev txiav txim ntawm cov amino acid linkage precisely tswj los ntawm codons kom ua tiav cov lus qhia kev sib dhos ntawm cov saw hlau polypeptide.
Spatial Structural Nta thiab Physicochemical Properties ntawm Peptide Bonds
Cov qauv kev sib txuas ntawm cov peptide daim ntawv cog lus txiav txim siab nws qhov tshwj xeeb spatial conformation: carbonyl oxygen thiab amino hydrogen nyob rau hauv ib qho kev teeb tsa, tsim lub kaum sab xis ntawm kwv yees li 120 °, uas yog ib qho kev sib koom ua ke (lub kaum sab xis dihedral ω yog ze rau 180 °). Cov txheej txheem no txwv tsis pub cov qib ntawm kev ywj pheej ntawm cov kaum sab xis dihedral (φ thiab ψ) ntawm α-carbons uas nyob ib sab, txhawb kev tsim cov txheej txheem thib ob hauv cov saw hlau polypeptide (xws li α-helices, β-cov ntawv, lossis β-tig). Nyob rau hauv cov nqe lus ntawm physicochemical zog, cov amide pab pawg neeg ntawm peptide daim ntawv cog lus yuav ua tau raws li ib tug hydrogen daim ntawv cog lus pub (amino hydrogen) thiab txais (carbonyl oxygen), koom nyob rau hauv kev tsim kho ntawm hydrogen bond network nyob rau hauv cov proteins thiab ntawm molecules. Nws cov txheej txheem conjugated nthuav tawm cov yam ntxwv ntawm kev nqus ntawm ultraviolet lub teeb ntawm wavelengths ntawm 210-230 nm, ua rau kom muaj nuj nqis ntawm cov protein ntau los ntawm ultraviolet spectrophotometric. Tsis tas li ntawd, cov tshuaj lom neeg ruaj khov ntawm cov peptide daim ntawv cog lus ua rau nws nyuaj rau kev ua kom tsis muaj zog hydrolysis hauv nruab nrab aqueous daws, tab sis nws tuaj yeem raug tshem tawm tshwj xeeb hauv qab catalysis ntawm proteases, ua lub hom phiaj tseem ceeb rau kev puas tsuaj ntawm cov protein.
Kev ua haujlwm lom neeg thiab kev siv thev naus laus zis ntawm Peptide Bonds
Nyob rau hauv lub neej kev ua ub no, dynamic tshuav nyiaj li cas ntawm peptide daim ntawv cog lus tswj proteome homeostasis: ntawm ib sab, kev ruaj ntseg ntawm lawv covalent linkages xyuas kom meej lub functionality ntawm lom macromolecules xws li enzymes thiab structural proteins; Ntawm qhov tod tes, cov ntawv cog lus tshwj xeeb peptide tau lees paub thiab hydrolyzed los ntawm proteases (xws li proteasome nyob rau hauv ubiquitin-proteasome system thiab lysosomal enzymes), ua kom tshem tawm cov protein ntau txawv txav thiab kev cai ntawm lub cev ntawm cov cim taw qhia. Hauv kev ua haujlwm ntawm biotechnology, cov khoom siv tshuaj lom neeg ntawm peptide bonds tau siv dav hauv polypeptide synthesis: hauv cov txheej txheem sib xyaw ua ke, cov tswv yim tiv thaiv pab pawg tau ua haujlwm los xaiv qhib cov carboxyl pawg ntawm cov amino acids rau kev taw qhia peptide daim ntawv cog lus. Protein sequencing cov tswv yim siv phenyl isothiocyanate los teb nrog N-terminal amino acid thiab xaiv cleave thawj peptide daim ntawv cog lus, ua kom muaj kev soj ntsuam ntawm qhov sib lawv liag. Tsis tas li ntawd, protease inhibitors tsim los ntawm peptide daim ntawv cog lus analogs thaiv cov chaw ua haujlwm ntawm cov enzymes los ntawm kev ua raws li kev sib raug zoo ntawm ntuj peptide bonds, dhau los ua lub tswv yim tseem ceeb hauv kev tsim tshuaj. Cov kev tshawb fawb tob txog cov qauv kev ua haujlwm ntawm kev sib raug zoo ntawm peptide daim ntawv cog lus txuas ntxiv mus rau kev tsim kho thev naus laus zis hauv kev tsim cov protein, kev txhim kho tshuaj polypeptide, thiab hluavtaws biology.
