NADH dehydrogenase of Corynebacterium glutamicum. Purification of an NADH dehydrogenase II homolog able to oxidize NADPH

NADPH oxidase activity, in addition to NADH oxidase activity, has been show n to be present in the respiratory chain of Corynebacterium glutamicum. In this study, we tried to purify NADPH oxidase and NADH dehydrogenase activit ies from the membranes of C glutamicum. Both the enzyme activities were sim ultaneously purified in the same fraction, and the purified enzyme was show n to be a single polypeptide of 55 kDa. The N-terminal sequence of the enzy me was consistent with the sequence deduced from the NADH dehydrogenase gen e of C glutamicum, which has been sequenced and shown to be a homolog of NA DH dehydrogenase II. In addition to high NADH-ubiquinone-1 oxidoreductase a ctivity at neutral pH, the purified enzyme showed relatively high NADPH oxi dase and NADPH-ubiquinone-1 oxidoreductase activities at acidic pH. Thus, N ADH dehydrogenase of C glutamicum was shown to be rather unique in having a relatively high reactivity toward NADPH. (C) 2001 Federation of European M icrobiological Societies. Published by Elsevier Science BN. All rights rese rved.