Feem ntau, peptides muaj ob mus rau cuaj amino acids. Nyob ntawm seb muaj pes tsawg tus amino acids nyob rau hauv peptide, muaj ntau lub npe rau peptide, xws li dipeptide, tripeptide, tetrapeptide, pentapeptide, thiab lwm yam. Peptides muaj peb lossis ntau dua amino acid molecules hu ua peptides, nrog rau qhov hnyav molecular hauv qab 10000. Da. Lawv tuaj yeem dhau los ntawm cov txheej txheem semi permeable thiab tsis yog los ntawm trichloroacetic acid thiab ammonium sulfate. Qee cov ntaub ntawv kuj hais txog peptides uas muaj 2-10 amino acids li oligopeptides (me me molecule peptides); Peptides muaj li ntawm 10 mus rau 50 amino acids hu ua peptides; Lub peptide muaj li ntawm 50 lossis ntau dua cov amino acids hu ua protein, hauv lwm lo lus, cov protein yog qee zaum hu ua polypeptide. Peptides, tseem hu ua peptides, tau pom nyob rau hauv lub xyoo pua 20th.
