Biosynthesis of Avian Glucagon: Evidence for a Possible High Molecular Weight Biosynthetic Intermediate[*]

Abstract

The biosynthesis of glucagon was examined using pigeon isolated islet preparation. Studies showed that radioactive tryptophan was incorporated into a large gel-filtration component, possessing glucagon immunoactivity. The radioactive component appeared homogeneous on Sephadex G-100 gelfiltration and polyacrylamide gel electrophoreses, and has a molecular weight of approximately 69,000. Tryptic hydrolysates of the large biosynthetic component contained radioactive peptides identifiable chromatographically with those obtained from a tryptic hydrolysate of bovine-porcine glucagon. These data suggested the biosynthesis of a high molecular weight glucagon-related protein in avian islets of Langerhans.

Key words

Avian Glucagon - Biosynthesis - Isolated Islets - Gel-Filtration - Polyacrylamide Gel Electrophoreses - Peptide Mapping

1 Parts of this work were presented at the IV International Congress of Endocrinology, Washington, D.C. June, 1972.

1 Parts of this work were presented at the IV International Congress of Endocrinology, Washington, D.C. June, 1972.

2 Present address: Department of Physiology, School of Medicine, University of Arkansas, Little Rock, Arkansas 72201, U.S.A.