Role of α-NADH for microsomal ethanol oxidation

α-NADH^* * Reduced form of α-isomer of nicotinamide adenine dinucleotide (1, 2). was found to serve as electron donor for microsomal ethanol oxidation of rat liver. Almost no ethanol oxidation was observed with β-NADH. The α-NADH-dependent ethanol oxidation was almost completely inhibited by 0.1 mM cyanide or azide and strongly abolished in the presence of formate. α-NADH-dependent ethanol oxidation was increased by 1 mM SKF-525A, an inhibitor of microsomal mixed-function oxidase, to about 200%. These results suggested that hydrogen peroxide generated from α-NADH and molecular oxygen in microsomes might be a prerequisite step in the over-all reaction, eventually leading to the peroxidatic ethanol oxidation by catalase to acetaldehyde.