The full content of Annals is available to subscribers

Subscribe/Learn More  >
Currents |

Connecting Peptide, Correcting Peptide?

Michelle Hoffman
[+] Article, Author, and Disclosure Information

Copyright ©2004 by the American College of Physicians

Ann Intern Med. 1997;127(12):1147-1148. doi:10.7326/0003-4819-127-12-199712150-00050
Text Size: A A A

In biochemistry textbooks, insulin is uniformly described as a small protein consisting of two peptide chains held together by disulfide bonds. Initially, the hormone is manufactured as a single precursor molecule called proinsulin, from which a connecting peptide (or C peptide) is later excised, leaving the mature insulin molecule (Figure 1). Most books continue with a description of insulin's role in lowering blood glucose levels and controlling lipolysis in adipose tissue, but C peptide is rarely mentioned again. Indeed, until recently, C peptide was viewed essentially as a waste product that played no role in regulation of metabolism or in the treatment of diabetes.


peptides ; c-peptide

First Page Preview

View Large
First page PDF preview


Grahic Jump Location
Figure 1.
C peptide (open circles) is cleaved from proinsulin at the dipeptides (Arg-Arg and Lys-Arg) to produce insulin (filled circles).

Two disulfide bonds connect insulin's A chain, composed of 21 amino acids, and B chain, composed of 30 amino acids. The A chain also contains a third disulfide bond.

Grahic Jump Location




Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).


Submit a Comment/Letter
Submit a Comment/Letter

Summary for Patients

Clinical Slide Sets

Terms of Use

The In the Clinic® slide sets are owned and copyrighted by the American College of Physicians (ACP). All text, graphics, trademarks, and other intellectual property incorporated into the slide sets remain the sole and exclusive property of the ACP. The slide sets may be used only by the person who downloads or purchases them and only for the purpose of presenting them during not-for-profit educational activities. Users may incorporate the entire slide set or selected individual slides into their own teaching presentations but may not alter the content of the slides in any way or remove the ACP copyright notice. Users may make print copies for use as hand-outs for the audience the user is personally addressing but may not otherwise reproduce or distribute the slides by any means or media, including but not limited to sending them as e-mail attachments, posting them on Internet or Intranet sites, publishing them in meeting proceedings, or making them available for sale or distribution in any unauthorized form, without the express written permission of the ACP. Unauthorized use of the In the Clinic slide sets will constitute copyright infringement.


Buy Now for $32.00

to gain full access to the content and tools.

Want to Subscribe?

Learn more about subscription options

Related Articles
Topic Collections
PubMed Articles
Forgot your password?
Enter your username and email address. We'll send you a reminder to the email address on record.