C-Peptide (C-Peptide) peptide ne mai haɗawa wanda ya ƙunshi amino acid 31 tare da nauyin kwayoyin kusan 3021 Daltons. Kwayoyin β-kwayoyin pancreatic na pancreas suna haɗa proinsulin, wanda shine sarkar furotin mai tsayi sosai. Proinsulin ya kasu kashi uku a karkashin aikin enzymes, kuma an sake haɗa sassan gaba da baya don zama insulin, wanda ya ƙunshi sarkar A da B, yayin da ɓangaren tsakiya ya kasance mai zaman kansa kuma an san shi da C-peptide. . Insulin da C-peptide ana ɓoye su a cikin ma'auni mai ma'ana, kuma bayan shiga cikin jini, yawancin insulin hanta ba ta aiki, yayin da C-peptide da wuya hanta ya ɗauka, tare da lalatawar C-peptide yana da hankali fiye da insulin. Matsakaicin C-peptide a cikin jini ya fi na insulin sama da na insulin, yawanci fiye da sau 5, don haka C-peptide daidai yana nuna aikin ƙwayoyin β-sel na pancreatic. Ana iya amfani da auna matakin C-peptide don rarrabuwa na ciwon sukari da kuma fahimtar aikin pancreatic β-cell na masu ciwon sukari mellitus. Za a iya amfani da ma'aunin matakin C-peptide don rarraba ciwon sukari da fahimtar aikin β-cell na pancreatic a cikin marasa lafiya da ciwon sukari. A halin yanzu, hanyoyin auna C-peptide da ake amfani da su sosai a asibitocin likita sun haɗa da radioimmunoassay, immunoassay enzyme, electrochemiluminescence, chemiluminescence.