Marino L, Muglia B, Dickinson C J
University of Michigan Medical Center, Department of Pediatrics, Ann Arbor 48109-0658.
Regul Pept. 1994 Feb 3;50(1):73-85. doi: 10.1016/0167-0115(94)90193-7.
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.
胆囊收缩素（CCK）和胃泌素是肠道中的两种多肽激素，它们的羧基末端五肽具有完全的结构同源性。这两种肽都是通过羧基末端α-酰胺化反应从其甘氨酸延伸的前体形式被生物激活的。在本研究中，我们使用区域特异性抗血清来表征哺乳动物肠道中胃泌素和CCK的羧基末端酰胺化形式和甘氨酸延伸形式。在小肠的大部分区域都检测到了胃泌素和CCK的多种酰胺化分子形式及其相应的甘氨酸延伸形式。尽管我们在大鼠十二指肠近端检测到了大量的甘氨酸延伸型CCK，但未检测到相应的酰胺化分子形式。相反，狗和猪的十二指肠近端同时含有甘氨酸延伸型和酰胺化CCK。这些发现表明，肽α-酰胺化酶的表达和活性可能存在肽、组织和物种特异性差异。
