Collect. Czech. Chem. Commun. 1990, 55, 1336-1350

Equations for calculating the constants of enzyme inhibition/activation by n inhibitors/activators

Vladimír I. Krupyanko

Institute of Biochemistry and Physiology of Microorganisms, U.S.S.R. Academy of Sciences, Pushchino, Moscow Region, 142292, U.S.S.R.


Based on the method of vector representation of enzyme reactions in three-dimensional K'mV' coordinates, equations for calculating the constants of enzyme inhibition Ki(n) and activation Ka(n) by two or more inhibitors/activators were deduced. Inhibition of calf alkaline phosphatase by anions of molybdic (MoO42-) and tungstic (WO42-) acid was studied. The constants of enzyme inhibition by each of these anions and by their mixture in the same concentration were determined. The value of the phosphatase inhibition constant obtained experimentally was compared with that calculated using the appropriate equation. The prospects of using the equations obtained to analyze the kinetics of enzyme inhibition/activation by two or more simultaneous inhibitors/activators and to assess the contribution of each of these compounds are discussed.