Interaction of two arginine residues in lactate oxidase with the enzyme flavin: conversion of FMN to 8-formyl-FMN.

ABSTRACT: Two arginine residues, Arg-181 and Arg-268, are conserved throughout the known family of FMN-containing enzymes that catalyze the oxidation of alpha-hydroxyacids. In the lactate oxidase from Aerococcus viridans, these residues have been changed to lysine in two single mutations and in a double mutant form. In addition, Arg-181 has been replaced by methionine to determine the effect of removing the positive charge on the residue. The effects of these replacements on the kinetic and thermodynamic properties are reported. With all mutant forms, there are only small effects on the reactivity of the reduced flavin with oxygen. On the other hand, the efficiency of reduction of the oxidized flavin by l-lactate is greatly reduced, particularly with the R268K mutant forms. The results demonstrate t

SUBMITTER: Yorita K 

PROVIDER: S-EPMC27174 | biostudies-literature | 2000 Nov

REPOSITORIES: biostudies-literature