Oxidation of naphthalene by a multicomponent enzyme system from Pseudomonas sp. strain NCIB 9816.

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Abstract
The initial reaction in the oxidation of naphthalene by Pseudomonas sp. strain NCIB 9816 involves the enzymatic incorporation of 1 molecule of O2 into the aromatic nucleus to form (+)-cis-(1R, 2S)-dihydroxy-1,2-dihydronaphthalene. The enzyme catalyzing this reaction, napthalene dioxygenase, was resolved into 3 protein components, designated A, B and C, by DEAE-cellulose chromatography. Incubation of naphthalene with components A, B and C in the presence of NADH resulted in the formation of (+)-cis-(1R,2S)-dihydroxy-1,2-dihydronaphthalene. The ratio of O2 and NADH utilization to product formation was 1:1:1. NADPH also served as an electron donor for naphthalene oxygenation. However, its activity was < 50% of that observed with NADH. Component A showed NAD(P)H-cytochrome c reductase activity which was stimulated by the addition of FAD and FMN. A similar stimulation was observed when these flavin nucleotides were added to the naphthalene dioxygenase assay system. Naphthalene dioxygenase has properties in common with both monooxygenase and dioxygenase multicomponent enzyme systems.