Purification and Properties of 3 Types of Monohydroxybenzoate Oxygenase from Rhodococcus erythropolis S-1

Abstract

Three types of monohydroxybenzoate oxygenase, salicylate 5-oxygenase (SAL5O) forming gentisate from salicylate, m-hydroxybenzoate 6-oxygenase (MHB6O) forming gentisate from m-hydroxybenzoate, and p-hydroxybenzoate 3-oxygenase (PHB3O) forming protocatechuate from p-hydroxybenzoate, were purified from a cell-free extract of Rhodococcus erythropolis S-1, a Gram-positive bacterium. Each purified enzyme was homogenous on native PAGE. Each enzyme was a tetramer having identical subunits, a flavoporotein containing FAD, and a NADH-dependent monooxygenase. The three enzymes were much alike in general enzymatic properties, but very different in substrate specificity.