NIST logo

Publication Citation: Kinetic Characterization of Chiral Biocatalysis of Cycloarenes by the Camphor 5-Monooxygenase Enzyme System

NIST Authors in Bold

Author(s): D A. Grayson; V L. Vilker;
Title: Kinetic Characterization of Chiral Biocatalysis of Cycloarenes by the Camphor 5-Monooxygenase Enzyme System
Published: June 15, 1999
Abstract: Redox enzyme mediated biocatalysis has the potential to regio - and stereo-specificity oxidive hydrocarbons producing valuable products with minimal by-product formation. In-vitro reactions of the Camphor (cytochrome P-450) 5-monooxygenase enzyme system with naphthalene-like substrates yield stereospecifically hydroxylated products from nonactivated hydrocarbons. Specifically, the enzyme system catalyzes the essentially stereospecific conversion of the cycloarene, tetralin (1,2,3,4-tetrahydronaphthalene) to (R)-1-tetralol ((R)-(-)-1,2,3,4-tetrahydro-1-naphthol). It is shown that this reaction obeys Michaelis-Menten kinetics and that the interactions between the enzyme subunits are not affected by the identity of the substrate. This subunit independence extends to the efficiency of NADH usage by the enzyme system -- subunit ratios do not affect efficiency, but substrate identity does. Tetralin is converted at an efficiency of 13 3%, whereas (R)-1-tetralol is converted at 7.8 0.7%. A model of this system based on Michaelis-Menten parameters for one subunit (Pdx: KM = 10.2 2 M and both substrates (tetralin: KM = 66 26 M, Ņmax = 0.11 0.04 s-1; and (R)-1-tetralol: KM = 2800 1300 M, Ņmax = 0.83 0.22 s-1) is presented and used to predict the consumption and production of all substrates, products, and cofactors.
Citation: Journal of Molecular Catalysis B-Enzymatic
Volume: 6
Issue: 6
Pages: pp. 533 - 547
Keywords: chiral biosynthesis;cytovchrome P450;tetralin
Research Areas: Life Sciences Research, Chemical Analysis