FORMALDEHYDE DISMUTASE ACTIVITIES IN GRAM-POSITIVE BACTERIA OXIDIZINGMETHANOL

Extracts of methanol-grown cells of Amycolatopsis methanolica and Myco bacterium gastri oxidized methanol and ethanol with concomitant reduct ion of N,N'-dimethyl-4-nitrosoaniline (NDMA). Anion-exchange chromatog raphy revealed the presence of a single enzyme able to catalyse this a ctivity in methanol- or ethanol-grown cells of M. gastri. A. methanoli ca, however, possessed two different enzymes, one of which was similar to the single enzyme found in M. gastri. The methanol: NDMA oxidoredu ctases (MNO) were purified to homogeneity from methanol-grown cells of A. methanolica and M. gastri. Both enzyme preparations showed similar relative molecular masses with subunits of M(r) 50 000 and 49 000, an d native enzymes of M(r) 268 000 and 255 000 (gel-filtration data for A. methanolica and M. gastri, respectively). Both enzymes also display ed a similar substrate specificity. They were active with methanol and various other primary alcohols (yielding the corresponding aldehydes) , polyols and formaldehyde. In addition, the MNO enzymes produced meth ylformate from methanol plus formaldehyde, and catalyzed formaldehyde dismutase and NADH-dependent formaldehyde reductase reactions. They di d not possess NAD(P)+- or dye-linked alcohol dehydrogenase or oxidase activities.