Synergistic inhibition of carboxypeptidase A by zinc ion and imidazole.
Zinc ion in solution yields a 560-fold enhancement in the kinetic inhibition of carboxypeptidase A by the simple heterocycle imidazole, behavior attributed to formation of a ternary complex of the three species. However, the effect is partially negated by formation of less-inhibitory Zn2+(C3H4N2)2-4 coordination complexes, providing for the enzyme an anomalous profile of catalytic rate versus imidazole concentration.
Mock
W L
WL
Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607-7061, USA. wlmock@uic.edu
Wang
L
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D000818:Animals; D001667:Binding, Competitive; D002268:Carboxypeptidases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D043422:Carboxypeptidases A; D002384:Catalysis / Q000187:drug effects; D002412:Cations / Q000494:pharmacology; D002417:Cattle; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles / Q000378:metabolism / Q000494:pharmacology*; D007700:Kinetics; D008956:Models, Chemical; D010179:Pancreas / Q000201:enzymology; D011522:Protons; D012996:Solutions; D015032:Zinc / Q000378:metabolism / Q000494:pharmacology*
D002412:Cations; D007093:Imidazoles; D011522:Protons; D012996:Solutions; C029899:imidazole; D002268:Carboxypeptidases; D043422:Carboxypeptidases A; D015032:Zinc