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 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 suna ɓoye a cikin ma'auni mai ma'ana, kuma bayan shiga cikin jini, yawancin insulin hanta ba ya aiki, yayin da C-peptide da wuya hanta ya ɗauka, da raunin C-peptide yana da hankali fiye da insulin, don haka yawan C-peptide a cikin jini ya fi na insulin girma, yawanci fiye da sau 5, aikin pancreapet yana aiki sosai. β-kwayoyin. 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. Ana 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.