C-Peptide: Oligopeptide Research Reference
31-amino acid connecting peptide cleaved from proinsulin, used as a marker of endogenous insulin secretion. This peptide or oligopeptide is studied for its b...
Chemical Identity
| Property | Value |
|---|---|
| Chemical Formula | C129H211N35O48 |
| Molecular Weight | 3020 Da |
| CAS Number | 59401-28-4 |
| Peptide Class | Connecting Peptide (31 amino acids) |
| Sequence | EAEDLQVGQVELGGGPGAGSLQPLALEGSLQ |
Structure
C-peptide is a 31-amino acid peptide that connects the A and B chains of proinsulin in the precursor molecule. During insulin biosynthesis, proinsulin is cleaved by prohormone convertases PC1/3 and PC2, releasing C-peptide and mature insulin in equimolar amounts.
Mechanism of Action
C-peptide was long considered biologically inactive, but evidence suggests it binds to a G-protein-coupled receptor (possibly CXCR4) on cell surfaces, activating eNOS and Na+/K+-ATPase. It may have beneficial effects on microvascular blood flow, nerve function, and renal function in type 1 diabetes.
Clinical Applications
- Beta-cell function assessment: C-peptide levels reflect endogenous insulin production
- Type 1 vs type 2 diabetes: Distinguishes insulin deficiency from resistance
- Hypoglycemia evaluation: Factitious vs insulinoma
- Research: Potential therapeutic in type 1 diabetes
Pharmacology
- Half-life: 20-30 minutes (vs 3-5 min for insulin)
- Molar ratio: 1:1 with insulin
- Renal clearance: 5% of insulin clearance
- Stability: More stable than insulin in blood samples
References
- Steiner, D.F., & Oyer, P.E. (1967). The biosynthesis of insulin. Proceedings of the National Academy Sciences, 57, 473-480.
- Wahren, J., et al. (2012). Role of C-peptide in human physiology. American Journal of Physiology, 298, E731-E740.
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