[Reduction of nitrazepam by rat liver mitochondria (author's transl)]

Highly purified rat liver mitochondria are able to reduce nitro groups of organic compounds to primary amines. This reductase-activity is bound to mitochondrial inner membrane or its matrix. It has no plain substrate specificity whereas it will attack the various substrates at widely different rates [nitrazepam (Mogadan) 1.7 times faster than 4-nitrobenzoic acid]. The activity was markedly inhibited under aerobic conditions. The rate of nitrazepam reduction by rat liver mitochondria was about 1/3--1/4 the rate by microsomal fraction, provided that both preparations contained the same protein amounts. NADH was required as a cofactor, but the nitroreduction was also stimulated by some Krebs cycle intermediates, especially by alpha-ketoglutarate. The reaction was markedly inhibited by organic solvents, even by little volumes. DMSO and DMF are cancelling every activity.