Differences in receptor binding and stability to enzymatic digestion between CCK-8 and CCK-58

Autor: Steven R. Vigna, Joseph R. Reeve, F. J. Ho, Michael T. Davis, Terry D. Lee, John E. Shively, Travis E. Solomon, Douglas C. McVey, David A. Keire, Nigel W. Bunnett
Rok vydání: 2002
Předmět:
Zdroj: Pancreas. 25(3)
ISSN: 1536-4828
Popis: It has been proposed that distinct tertiary structures of the C-terminus of CCK-8 and CCK-58 result in differences in stimulation of pancreatic amylase secretion. Binding of CCK-8 and CCK-58 to CCK-A and CCK-B receptors and stability to enzymatic digestion were used as independent probes for tertiary structure of the C-terminus.Canine CCK-58 was purified from intestinal extracts and CCK-8 was purchased. Their amounts were determined by amino acid analysis. The effect of tertiary structure on receptor binding at CCK-A receptors and CCK-B receptors was evaluated using membrane preparations from mouse pancreas and brain. The influence of C-terminal tertiary structure on stability to enzymatic digestion was evaluated by reacting CCK-8 and CCK-58 with endopeptidase 24:11.CCK-58 was three times more potent than CCK-8 for binding mouse pancreatic membrane CCK-A receptors and equipotent to CCK-8 for binding mouse brain CCK-B receptors. CCK-8 was readily digested by endopeptidase 24:11, whereas CCK-58 was not.The results strongly support the hypothesis that differences in tertiary structure of the carboxyl terminus of CCK-8 and CCK-58 influence receptor binding and stability to enzymatic digestion.
Databáze: OpenAIRE