YPolypeptide vs Protein
Amino acid yog ib qho yooj yim molecule tsim nrog C, H, O, N thiab tej zaum yuav yog S. Nws muaj cov qauv hauv qab no.
Muaj txog 20 hom amino acids. Tag nrho cov amino acids muaj -COOH, -NH2 pawg thiab -H sib txuas rau carbon. Cov pa roj carbon monoxide yog chiral carbon, thiab alpha amino acids yog qhov tseem ceeb tshaj plaws hauv lub ntiaj teb lom neeg. Cov pab pawg R sib txawv ntawm cov amino acid rau amino acid. Qhov yooj yim amino acid nrog R pawg ua H yog glycine. Raws li cov pab pawg R, cov amino acids tuaj yeem muab faib ua aliphatic, aromatic, tsis muaj polar, polar, zoo them, tsis zoo, lossis polar uncharged, thiab lwm yam. Amino acids tam sim no raws li zwitter ions nyob rau hauv lub cev pH 7.4. Amino acids yog lub tsev blocks ntawm cov proteins. Thaum ob lub amino acids koom ua ke los tsim ib lub dipeptide, kev sib xyaw ua ke yuav tshwm sim hauv -NH2 pawg ntawm ib cov amino acid nrog -COOH pawg ntawm lwm cov amino acid. Ib qho dej molecule raug tshem tawm, thiab daim ntawv cog lus tsim yog hu ua peptide daim ntawv cog lus.
YPolypeptide
Cov saw hlau tsim thaum muaj ntau cov amino acids koom ua ke yog hu ua polypeptide. Cov proteins muaj ib lossis ntau dua ntawm cov saw hlau polypeptide. Cov qauv tseem ceeb ntawm cov protein yog hu ua polypeptide. Los ntawm ob lub terminals ntawm polypeptide saw, N-terminus yog qhov chaw ntawm cov amino pawg dawb, thiab cov c-terminus yog qhov twg pawg carboxyl dawb. Polypeptides yog synthesized ntawm ribosomes. Cov amino acid sequence nyob rau hauv polypeptide saw yog txiav txim los ntawm cov codons nyob rau hauv mRNA.
YProtein
Proteins yog ib hom tseem ceeb tshaj plaws ntawm macromolecules hauv cov kab mob nyob. Proteins tuaj yeem raug faib ua thawj, theem nrab, qib thib ob thiab quaternary proteins nyob ntawm lawv cov qauv. Qhov sib lawv liag ntawm cov amino acids (polypeptide) nyob rau hauv ib tug protein yog hu ua ib tug thawj qauv. Thaum cov txheej txheem polypeptide quav mus rau hauv kev sib koom ua ke, lawv paub tias yog cov proteins thib ob. Hauv cov txheej txheem tertiary proteins muaj peb qhov qauv. Thaum ob peb seem protein moieties khi ua ke, lawv tsim cov quaternary proteins. Cov qauv peb sab ntawm cov protein nyob ntawm qhov sib txuas ntawm hydrogen, disulfide bonds, ionic bonds, hydrophobic interactions thiab tag nrho lwm yam kev sib cuam tshuam hauv cov amino acids. Proteins ua si ntau lub luag haujlwm hauv lub neej. Lawv koom nrog kev tsim cov qauv. Piv txwv li, cov leeg muaj protein ntau fibers xws li collagen thiab elastin. Lawv kuj pom muaj nyob rau hauv cov txheej txheem nyuaj thiab nruj xws li cov rau tes, plaub hau, hooves, plaub, thiab lwm yam. Cov proteins ntxiv muaj nyob rau hauv cov ntaub so ntswg zoo li pob txha mos. Tsis zoo li cov qauv kev ua haujlwm, cov proteins muaj kev tiv thaiv ib yam nkaus. Cov tshuaj tiv thaiv yog cov proteins, thiab lawv tiv thaiv peb lub cev los ntawm cov kab mob txawv teb chaws. Tag nrho cov enzymes yog cov proteins. Enzymes yog lub ntsiab molecules uas tswj tag nrho cov haujlwm metabolic. Tsis tas li ntawd, cov proteins koom nrog hauv cell signaling. Proteins yog tsim los ntawm ribosomes. Protein ua teeb liab raug xa mus rau ribosome los ntawm cov noob hauv DNA. Qhov xav tau cov amino acids tuaj yeem yog los ntawm kev noj zaub mov lossis tuaj yeem ua rau hauv lub cell. Protein denaturation ua rau kev nthuav tawm thiab kev tsis sib haum xeeb ntawm cov proteins 'thib ob thiab tertiary qauv. Qhov no tuaj yeem yog vim cua sov, cov kuab tshuaj organic, cov kua qaub thiab cov hauv paus, cov tshuaj detergents, mechanical force, thiab lwm yam.
Qhov txawv ntawm Polypeptide thiab Protein yog dab tsi?
• Polypeptides yog cov amino acid sequence, whereas proteins yog tsim los ntawm ib los yog ntau tshaj polypeptide chains.
• Proteins muaj qhov hnyav dua molecular dua li polypeptides.
• Proteins muaj hydrogen bonds, disulfide bonds thiab lwm yam electrostatic kev sib cuam tshuam, uas tswj nws peb seem qauv nyob rau hauv sib piv rau polypeptides.
