METABOLISM OF AROMATIC COMPOUNDS BY BACTERIA,

I. GENTISIC ACID OXIDASE AND PROTOCATECHUIC ACID OXIDASE OF PSEUDOMONAS OVALIS S-5

Abstract

1. Gentisic acid oxidase was obtained as cell-free extract from the cells of Pseudomonas ovalis S-5 which had been induced by m-hydroxybenzoic acid. Its purification and investigation of its properties were carried out, and the facts that this enzyme was a new ring splitting enzyme and required ferrous ion as a sole co-factor, were demonstrated.
2. Fumarylpyruvic acid which is the product of the ring cleavage, was obtained as crystalline form, and identified. Maleylpyruvic acid which is initial intermediate was recognized spectrophotometrically, and the metabolic pathway of gentisic acid oxidation was established.
3. Protocatechuic acid oxidase which was contaminated in crude extract, is constitutive enzyme in the cells of Ps. Ovalis, and was purified. As the results from investigation of its properties, this enzyme also requires ferrous ion as a co-factor, and produces β-carboxymuconic acid.
4. In secondary induction procedure, the inductive formation of m- hydroxybenzoic and gentisic acids oxidizing enzymes by intact cells prepared from the stationary phase were the strongest. Oxygen was necessary to this enzyme formation, however, the addition of glucose as energy source was ineffective. And other factors which influence to secondary induction procedure, were determined.