In vivo synthesis of cholecystokinin in the rat cerebral cortex: identification of COOH-terminal peptides with labeled amino acids.
The synthesis of the COOH-terminal octa- and tetrapeptides of cholecystokinin (CCK) has been studied in rat cerebral cortex after intraventricular administration of radioactive amino acids characteristic of the porcine COOH-terminal octapeptide of CCK, CCK-8. After immunosorption with a COOH-terminal directed antibody, cortical CCK was fractionated on Sephadex G-50 columns. The experiments demonstrated newly synthesized CCK forms which coeluted with porcine CCK-8 and CCK-4. Except for threonine the amino acids employed, methionine, tryptophan, aspartic acid, glycine and phenylalanine were incorporated. The sequence-specific radioimmunoassay, the incorporation of the employed labeled amino acids, and the elution pattern by gel filtration, suggest an almost identical structure of porcine and rat cortical CCK-8, and a concomitant synthesis of CCK-8 and CCK-4 in rat cerebral cortex.
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D002766:Cholecystokinin / Q000096:biosynthesis*; D008297:Male; D009842:Oligopeptides / Q000096:biosynthesis; D011863:Radioimmunoassay; D011865:Radioisotope Dilution Technique; D051381:Rats; D011919:Rats, Inbred Strains
D000596:Amino Acids; D009842:Oligopeptides; D002766:Cholecystokinin