title: Impaired alpha-carboxyamidation of gastrin in vitamin C-deficient guinea pigs.
abstract: The biosynthetic activation of many hormonal peptides requires enzymatic alpha-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 necessary for alpha-carboxyamidation in vivo, and thus, that the biosynthetic activation of hormonal peptides can be modified by simple dietary means.
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000502:physiology; D004032:Diet; D005755:Gastrins / Q000378:metabolism*; D005998:Glycine / Q000378:metabolism; D006168:Guinea Pigs; D010446:Peptide Fragments / Q000032:analysis; D012614:Scurvy / Q000378:metabolism*
chemical_list: D005755:Gastrins; D010446:Peptide Fragments; D001205:Ascorbic Acid; D005998:Glycine