C-Peptide (C-Peptide) bụ peptide njikọ nke mejupụtara amino acid 31 nwere ịdị arọ molekul nke ihe dịka 3021 Daltons. Mkpụrụ ndụ β-pancreatic nke pancreas na-emepụta proinsulin, nke bụ eriri protein dị ogologo. A na-agbaji Proinsulin ụzọ atọ n'okpuru ọrụ nke enzymes, a na-ejikọkwa akụkụ ihu na azụ ka ọ bụrụ insulin, nke mejupụtara yinye A na B, ebe etiti etiti nwere onwe ya ma mara ya dị ka C-peptide. . A na-ezobe insulin na C-peptide na mkpokọta nha nha, ma mgbe ịbanye n'ọbara, imeju na-eme ka ọtụtụ insulin kwụsị ọrụ, ebe C-peptide adịghị adịkarị na imeju, gbakwunyere mmebi nke C-peptide dị nwayọ karịa insulin. Ntinye uche nke C-peptide n'ime ọbara dị elu karịa nke insulin, na-abụkarị ihe karịrị ugboro 5, yabụ C-peptide na-egosipụta n'ụzọ ziri ezi na ọrụ nke sel β-sel pancreatic. Enwere ike iji tụọ ọkwa C-peptide maka nhazi nke ọrịa shuga mellitus yana ịghọta ọrụ nke mkpụrụ ndụ β-pancreatic nke ndị ọrịa shuga mellitus. Enwere ike iji nha ọkwa C-peptide iji wepụta ọrịa shuga ma ghọta ọrụ β-cell pancreatic na ndị ọrịa nwere ọrịa shuga. Ugbu a, usoro nha C-peptide nke a na-ejikarị na ụlọọgwụ ahụike gụnyere radioimmunoassay, enzyme immunoassay, electrochemiluminescence, chemiluminescence.