[Two ways of formate oxidation in methylotrophic bacteria]

The cells of Achromobacter parvulus, strain 1T, when grown in a methanol-containing medium, have two formate dehydrogenases, i.e. NAD-linked formate dehydrogenase and the formate dehydrogenase reducing the ferricyanide and tetrazolia. Only the latter enzyme was found in the cells grown in a medium with glycerol as a carbon source. These enzymes differ with respect to Km for formate and antigenic specificity. Km for formate oxidation by the cells of A. parvulus is lower than for formate of the NAD-dependent formate dehydrogenase and is equal to Km for the enzyme reducing artificial electron acceptors. The results obtained are discussed in terms of the existence of two cytochrome oxidase systems in the methylotrophic bacteria, differing in their sensitivities to the inhibition by formate.