Alpha-carboxyamidation of antral progastrin. Relation to other post-translational modifications.

摘要: Abstract Using radioimmunoassays for amidated and glycine-extended gastrin before after trypsin-carboxypeptidase B cleavage chromatography, alpha-carboxyamidation of porcine antral progastrin has been related to tyrosine-O-sulfation proteolytic cleavages. Corresponding the sequence at proteolysis amidation site, -Gly-Arg-Arg-, antrum contained three COOH-terminally extended precursor types. The gastrins were present in highest concentrations (241 +/- 58 pmol/g). degree was identical irrespective component size, whereas size differed forms. For instance, gastrin-34-Gly constituted 54% gastrins, while gastrin-34 comprised 8% gastrins. results indicate that occurs prior NH2-terminal cleavages, which again precede carboxyamidation; but a significant correlation between cleavages or alpha-carboxy-amidation could not be demonstrated. Furthermore, our suggest immediate principal hormonal form, gastrin-17, is gastrin-17-Gly rather than as previously believed.