Donald F. Steiner, "The Proinsulin C-peptide—A Multirole Model", Journal of Diabetes Research, vol. 5, Article ID 749857, 8 pages, 2004. https://doi.org/10.1080/15438600490424389
The Proinsulin C-peptide—A Multirole Model
The C-peptide links the insulin A and B chains in proinsulin, providing thereby a means to promote their efficient folding and assembly in the endoplasmic reticulum during insulin biosynthesis. It then facilitates the intracellular transport, sorting, and proteolytic processing of proinsulin into biologically active insulin in the maturing secretory granules of the β cells. These manifold functions impose significant constraints on the C-peptide structure that are conserved in evolution. After cleavage of proinsulin, the intact C-peptide is stored with insulin in the soluble phase of the secretory granules and is subsequently released in equimolar amounts with insulin, providing a useful independent indicator of insulin secretion. This brief review highlights many aspects of its roles in biosynthesis, as a prelude to consideration of its possible additional role(s) as a physiologically active peptide after its release with insulin into the circulation in vivo.
Copyright © 2004 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.