Glycine-extended post-translational processing intermediates of gastrin and cholecystokinin in the gut.
Cholecystokinin (CCK) and gastrin are two polypeptide hormones of the gut that share complete structural homology in their carboxyl-terminal pentapeptide. Both peptides are biologically activated from their glycine-extended precursor forms by a carboxyl-terminal alpha-amidation reaction. In the present studies we used region specific antisera to characterize the carboxyl-terminally amidated and glycine-extended forms of gastrin and CCK in mammalian intestine. Multiple amidated molecular forms of gastrin and CCK and their corresponding glycine-extended forms were detected throughout the most of the small bowel. Although, we detected substantial amounts of glycine-extended CCK in the proximal rat duodenum, we detected none of the corresponding amidated molecular forms. In contrast, the proximal duodenum of dog and hog contained both glycine-extended and amidated CCK. These findings suggest that there may be peptide, tissue and species specific differences in expression and activity of the peptide alpha-amidating enzyme.
Marino
L
L
University of Michigan Medical Center, Department of Pediatrics, Ann Arbor 48109-0658.
Muglia
B
B
Dickinson
C J
CJ
D000595:Amino Acid Sequence; D000818:Animals; D002766:Cholecystokinin / Q000737:chemistry / Q000378:metabolism*; D004285:Dogs; D004386:Duodenum / Q000378:metabolism; D005755:Gastrins / Q000737:chemistry / Q000378:metabolism*; D005998:Glycine / Q000737:chemistry*; D007421:Intestine, Small / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D014176:Protein Biosynthesis; D011498:Protein Precursors / Q000737:chemistry / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D013045:Species Specificity; D013552:Swine
D005755:Gastrins; D011498:Protein Precursors; D002766:Cholecystokinin; D005998:Glycine