Factors Affecting Deoxycholate Inactivation and Mg ++ Reactivation of Bacillus megaterium KM Membrane Nicotinamide Adenine Dinucleotide (Reduced Form) Oxidase

Decay of the reduced nicotinamide adenine dinucleotide oxidase ofBacillus megaterium KM membranes was prevented by storage in 10% (v/v) glycerol or 0.4% bovine serum albumin. Differential rates of solubilization of components of the oxidase system by 0.4% deoxycholate was demonstrable at 4 C. The amount of Mg++ necessary for maximal oxidase reactivation increased with increasing amounts of deoxycholate-inactivated oxidase. Mg++ activation of deoxycholate-inactivated oxidase was partially temperature-dependent. Maximal activation was observed at 37 C, but only partial activation took place at 4 C. A small amount of deoxycholate was required for Mg++ activation of deoxycholate-inactivated oxidase. Twop H optima were found for Mg++ activation of deoxycholate-inactivated oxidase,p H 5.3 and 7.3. Significant amounts of activation of the inactive oxidase occurred in the absence of Mg++ with an optimum atp H 5.0, with essentially no Mg++ -independent activation demonstrable atp H 7.0.