Impaired α‐carboxyamidation of gastrin in vitamin C‐deficient guinea pigs

Abstract

The biosynthetic activation of many hormonal peptides requires enzymatic a-carboxyamidation via glycine-extended intermediate forms. By specific radioimmunochemical measurement on extracts of guinea pig antra, we found that vitamin C deficiency induced a 30-fold increase in glycine-extended (i.e. inactive) gastrins. The results indicate that ascorbic acid is neccessary for α-carboxyamidation in vivo, and thus, that the biosynthetic activation of hormonal peptides can be modified by simple dietary means.