THE MICROCALORIMETRIC STUDIES ON THE INHI BITION-KINETICS OF ENZYME-CATALYZED REACTION - FLUORIDE-ION INHIBITING LACCASE-CATALYZED OXIDATION REACTION OF O-PHENYLENEDIAMINE

Thermokinetic equation is proposed as Omega(0)(-1) = A[S-0](-1) + B, w hich is available for all kinds of reversible inhibitions of single-su bstrate enzyme-catalyzed reactions, According to the relations between A/B, B and K-m, Omega(m), the type of the reversible inhibition can b e judged as competitive, non-competitive and uncompetitive inhibitions . The thermokinetic formula which can be used to calculated the appare nt Michaelis constant K-m,K-app, inhibition constant K-i and so on are given. The theory proposed has been applied to the kinetic determinat ion of laccase-catalyzed oxidation reaction of o-phenylenediamine inhi bited by fluoride ion, The experimental result shows that this reactio n belongs to non-competitive inhibition, K-m,K-app = 9.712 x 10(-2) mo l . L(-1), K-i = 2.090 x 10(-2) mol . L(-1).