TWO TYPES OF HYDROQUINONE OXIDASE OF PSEUDOMONAS AERUGINOSA

Abstract

Pseudomonas aeruginosa contains besides P-cytochrome oxidase, an enzyme which can be extracted in a water-soluble state and which oxidizes hydro-quinone, L-ascorbate and p-phenylenediamine (the rate decreasing in this order) without addition of any cofactor. This enzyme was purified about 19 fold starting from an extract of acetone-powder of the cells. The most purified preparation had no cytochrome-like absorption spectrum and could not oxidize reduced P-cytochrome₅₅₁ or reduced P-blue protein, the sub-strates which are oxidized by P-cytochrome oxidase. Unlike P-cytochrome oxidase, oxidation of hydroquinone by this enzyme is scarcely influenced by cyanide or carbon monoxide. Increase of oxygen tension up to 100 per cent results in a gradual increase in the oxidative rate.
This enzyme was tentatively named Pseudomonas hydroquinone oxidase, since hydroquinone was the most rapidly oxidized of the substrates tested and since its true biological function is not yet known.
The author would like to express his thanks to Prof. K. Okunuki and Dr. T. Horio for their valuable guidance. Thanks are also due to his colleagues Messrs. M. Nozaki, T. Yamanaka, J. Yamashita and H. Mizushima of the same laboratory for their help and discussion and Messrs. M. Nakai and K. Kusai of Ama-gasaki Factory of Nagase & Co., Ltd., for mass-culture of the microörganisms.