The microbial oxidation of methanol. The prosthetic group of the alcohol dehydrogenase of Pseudomonas sp. M27: a new oxidoreductase prosthetic group.

1. The purified alcohol dehydrogenase of Pseudomonas sp. M27, whose action is independent of nicotinamide nucleotides, has absorption peaks at 280mmu and at 350mmu with little or no absorption at or above 450mmu. 2. It does not fluoresce, but green-fluorescent material, diffusible on dialysis, is produced when the enzyme is treated with acid or alkali or when it is boiled. 3. Evidence is presented that the enzyme is not a flavoprotein. 4. Kinetic studies show a correlation between enzyme inactivation by acid, alkali or heat and liberation of the fluorescent material. 5. Some purification of the fluorescent material was achieved, but definite identification was not possible; the major component has a fluorescence maximum at about 460mmu with excitation maxima at about 260mmu and 365mmu. 6. Data are given (including absorption and fluorescence spectra) that support the suggestion that the prosthetic group of the enzyme is a pteridine derivative. 7. Possible mechanisms of action of the enzyme are discussed.