Kinetics of inactivation of bovine pancreatic ribonuclease A by bromopyruvic acid.
The kinetic theory of substrate reaction during the modification of enzyme activity [Duggleby (1986) J. Theor. Biol. 123, 67-80; Wang and Tsou (1990) J. Theor. Biol. 142, 531-549] has been applied to a study of the inactivation kinetics of ribonuclease A by bromopyruvic acid. The results show that irreversible inhibition belongs to a non-competitive complexing type inhibition. On the basis of the kinetic equation of substrate reaction in the presence of the inhibitor, all microscopic kinetic constants for the free enzyme, the enzyme-substrate complex and the enzyme-product complex have been determined. The non-competitive inhibition type indicates that neither the substrate nor the product affects the binding of bromopyruvic acid to the enzyme and that the ionization state of His-119 may be the same in both the enzyme-substrate and the enzyme-product complexes.
Wang
M H
MH
National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, beijing, People's Republic of China.
Wang
Z X
ZX
Zhao
K Y
KY
D000818:Animals; D002417:Cattle; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007700:Kinetics; D008956:Models, Chemical; D010179:Pancreas / Q000201:enzymology*; D011773:Pyruvates / Q000494:pharmacology*; D012259:Ribonuclease, Pancreatic / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013379:Substrate Specificity
D004791:Enzyme Inhibitors; D011773:Pyruvates; C017092:bromopyruvate; D012259:Ribonuclease, Pancreatic