C-peptide microheterogeneity in type 2 diabetes populations.
OBJECTIVE
The purpose of this study was to investigate naturally occurring C-peptide microheterogeneity in healthy and type 2 diabetes (T2D) populations.


METHODS
MS immunoassays capable of simultaneously detecting intact C-peptide and variant forms were applied to plasma samples from 48 healthy individuals and 48 individuals diagnosed with T2D.


RESULTS
Common throughout the entire sample set were three previously unreported variations of C-peptide. The relative contribution of one variant, subsequently identified as C-peptide (3-31), was found to be more abundant in the T2D population as compared to the healthy population. Dipeptidyl peptidase IV is suspected to be responsible for this particular cleavage product, which is consistent with the pathophysiology of T2D.


CONCLUSIONS
C-peptide does not exist in the human body as a single molecular species. It is qualitatively more heterogeneous than previously thought. These results lay a foundation for future studies devoted to a comprehensive understanding of C-peptide and its variants in healthy and diabetic populations.
The Biodesign Institute at Arizona State University, Tempe, 85287, USA.
Paul E
PE
Oran
Jason W
JW
Jarvis
Chad R
CR
Borges
Randall W
RW
Nelson
D000328:Adult; D000595:Amino Acid Sequence; D002096:C-Peptide / Q000737:chemistry / Q000378:metabolism*; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D002096:C-Peptide