DISSOLUTION-ENZYME KINETICS OF 11-BETA-HYDROXYLATION OF CORTEXOLONE BY CURVULARIA-LUNATA

The enzyme kinetics of 11β-hydroxylation of cortexolone by whole cells of Curvularia lunata were studied, taking into account the dissolution of the solid substrate. The dissolution behavior of substrate steroid was represented by an empirical expression. A mathematical model was developed to describe the heterogeneous process of steroid hydroxylation, based on the rate of enzyme reaction and the rate of substrate dissolution. The rate of 11β-hydroxylation of solubilized cortexolone coexisting with its solid form was found to be identical to Michaelis-Menten kinetics. The kinetic constants were estimated using experimental data. The good agreement between correlated and experimental values supported the suitability of the established model. © 1990.