Enzyme Activities Related to the Methanol Oxidation of Mycobacterium sp. strain JC1 DSM 3803

Mycobacterium sp. strain JC1 DSM 3803 grown in methanol showed no methanol dehydrogenase or oxidase activities found in most methylotrophic bacteria and yeasts, respectively. Even though the methanol-grown cells exhibited a little methanol-dependent oxidation by cytochrome c-dependent methanol dehydrogenase and alcohol dehydrogenase, they were not the key enzymes responsible for the methanol oxidation of the cells, in that the cells contained no c-type cytochrome and the methanol oxidizing activity from the partially purified alcohol dehydrogenase was too low, respectively. In substrate switching experiments, we found that only a catalase-peroxidase among the three types of catalase found in glucose-grown cells was highly expressed in the methanol-grown cells and that its activity was relatively high during the exponential growth phase in Mycobacterium sp. JC1. Therefore, we propose that catalase-peroxidase is an essential enzyme responsible for the methanol metabolism directly or indirectly in Mycobacterium sp. JC1.