Metals influence the hormone C-peptide related to insulin

Metals such as zinc, copper and chromium bind and influence a peptide involved in insulin production, according to new work by chemists from the University of California at Davis. The research is part of a new field of "metalloendocrinology" that examines in detail the role of metals in the biological processes of the body.

"We ask questions of people who did not realize we did not have an answer," said Marie Heffern, assistant professor of chemistry at UC Davis and lead author of the newspaper, to appear in the newspaper. ChemBioChem.

Metals play a role in many biochemical processes. Hemoglobin contains iron and carries oxygen to the blood; zinc and copper are involved in one-third to one-half of the body's functions. But if scientists know the overall amount of an element in a given component of the body, such as blood, they usually do not know the exact location of these metals, their state or their biological role in the body .

"A metal is an ingredient – what you do with it is what makes the difference," Heffern said. His laboratory at UC Davis uses new techniques to understand how metals are distributed inside and outside cells, how they bind to proteins and other molecules, and subtle influences. that they exert on these molecules.

The new study examined peptide C, or peptide linker, a short chain of amino acids. The potential of peptide C is studied in the treatment of renal failure and nerve damage of diabetes. A better understanding of how it behaves under different conditions might therefore be helpful in developing a drug.

Influence shape and absorption by cells

When the pancreas produces insulin, C peptide connects two insulin chains during a preliminary stage. Peptide C is then cut out, stored with insulin and released at the same time. Peptide C was once considered a byproduct of insulin production, but scientists now know that it acts as a hormone in its own right.

The researchers measured the ease with which zinc, copper, and chromium were bound to peptide C in specimens, as well as the impact of metals on cells' ability to absorb C-peptide.

The metals had subtle effects on the structure of the peptide C, especially its ability to wind helically under certain conditions. Copper and chromium prevented the cells from taking the hormone, but other metals such as zinc, cobalt, and manganese did not have such an effect.

The results show that metals can potentially "adjust" the activity of hormones such as peptide C by altering their structure or affecting their uptake into cells, Heffern said. Michael Stevenson, Postdoctoral Fellow, Kylie Uyeda, Research Specialist, Jessica San Juan, Graduate Student, and Ian Farran, Undergraduate Student in Biochemistry and Molecular Biology.