Measurement of precursors for alpha-amidated hormones by radioimmunoassay of glycine-extended peptides after trypsin-carboxypeptidase B cleavage.
Using fragment 5-17 of human gastrin-17 extended with glycine at the C-terminus as hapten, three of six rabbits produced high-titer, high-avidity antisera specific for glycine-extended gastrins. In combination with trypsin and carboxypeptidase B cleavage, radioimmunoassays based on these antisera measured progastrins in some extra-antral tissues and certain malignant tumors. The results show that sequential cleavage with trypsin and carboxypeptidase B followed by radioimmunoassay of glycine-extended peptides is a rapid and accurate procedure for measurement of biosynthetic precursors of alpha-amidated peptide hormones. Moreover, the procedure seems promising in the search for tumor markers.
D000818:Animals; D043424:Carboxypeptidase B; D002268:Carboxypeptidases; D002766:Cholecystokinin / Q000032:analysis; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D005755:Gastrins / Q000032:analysis; D005998:Glycine; D006728:Hormones / Q000032:analysis*; D006801:Humans; D006868:Hydrolysis; D011498:Protein Precursors / Q000032:analysis*; D011863:Radioimmunoassay; D013552:Swine; D014357:Trypsin; D015043:Zollinger-Ellison Syndrome / Q000032:analysis
D005755:Gastrins; D006728:Hormones; D011498:Protein Precursors; D002766:Cholecystokinin; D002268:Carboxypeptidases; D043424:Carboxypeptidase B; D014357:Trypsin; D005998:Glycine