ISOLATION AND PROPERTIES OF REDUCED NICOTINAMIDE ADENINE DINUCLEOTIDE-RUBREDOXIN OXIDOREDUCTASE OF CLOSTRIDIUM-ACETOBUTYLICUM

NADH-rubredoxin oxidoreductase from C. acetobutylicum was purified to yield a single band on disc-gel electrophoresis. The MW was 41,000 and did not dissociate into subunits when treated with sodium dodecyl sulfate and 2-mercaptoethanol. The prosthetic group of the enzyme was identified as FAD. The enzyme reduces rubredoxine, ferricyanide dichlorophenolindophenol, p-toluoquinone, p-benzoquinone, 1,4-naphtoquinone but not ferredoxin or flavodoxin. The reaction does not occur when NADPH is substituted for NADH. The NADH-rubredoxin reductase was extremely sensitive to the thiol inhibitors.