In [ l ] low concentrations of Tinopal AN, (1,l-bis(3,N-5-dimethylbenzoxazol-2-y1)methine p-toluene sulphonate), which is present in the optical brightener Uvitex AN (Ciba-Geigy Ltd) [2], inhibited the aerobic respiration of Paracoccus denitrificans. Using inverted membrane vesicles of P. denitrifcans [I], this inhibition was shown to occur in the NADH dehydrogenase (EC 1.66.99.3) region of the...

Accumulation of sorbitol in the tissue is known to cause microvascular diabetic complications. In this paper, a fiber-optic biosensor for sorbitol which is used as a biomarker of diabetic complications was developed and tested. The biosensor used a sorbitol dehydrogenase from microorganisms of the genus Flavimonas with high substrate specificity and detected the fluorescence of reduced nicotina...

Amphibacillus xylanus Ep01, a facultative anaerobe we recently isolated, shows rapid aerobic growth even though it lacks a respiratory pathway. Thus, the oxidative consumption of NADH, produced during glycolysis and pyruvate oxidation, should be especially important for maintenance of intracellular redox balance in this bacterium. We purified a flavoprotein functional as NADH oxidase from aerob...

NADH dehydrogenase is a key component of the respiratory chain. It catalyzes the oxidation of NADH by transferring electrons to ubiquinone and establishes a proton motive force across the cell membrane. The yjlD (renamed ndh) gene of Bacillus subtilis is predicted to encode an enzyme similar to the NADH dehydrogenase II of Escherichia coli, encoded by the ndh gene. We have shown that the yjlC-n...

Purified preparations of the reduced nicotinamide adenine dinucleotide dehydrogenase of the respiratory chain, extracted with the aid of phospholipase at moderate temperature, do not catalyze the reduction of long chain coenzyme Q derivatives (Q6 and QIO) at significant rates and are not inhibited by amytal or rotenone. On exposure of the enzyme to conditions which have been used for the extrac...

The plastoquinone antagonist 2,5-dibromothymoquinone was found to inhibit NO-3 reduction from NADH by the nitrate reductase complex from wheat. It accepts electrons from NADH through the NADH dehydrogenase activity of the nitrate reductase. However, it does not inhibit the reduction of 2,6-dichlorophenol-indophenol by the enzyme. This suggests that the two compounds may be accepting electrons a...

1. Several ring-substituted derivatives of diphenyleneiodonium catalyse the exchange of Clh and OHions across the inner membrane of rat liver mitochondria. They also inhibit state 3 and state 3u oxidations of glutamate plus malate in the presence of Cl more than in its absence. Most have activities similar to diphenyleneiodonium, although 2,4dichlorodiphenyleneiodonium is up to 50 times more ac...

Methyl methanethiosulphonate was used to produce a modification of the essential thiol group in lactate dehydrogenase which leaves the enzyme catalytically active. Methyl methanethiosulphonate produced a progressive inhibition of enzyme activity, with 2mM-pyruvate and 0.14mM-NADH as substrates, which ceased once the enzyme had lost 70-90% of its activity. In contrast, with 10mM-lactate and 0.4m...

The human lactate dehydrogenase isoform A plays an important role in the anaerobic metabolism of tumour cells and therefore constitutes an attractive target in the oncology field. Full-atom models of lactate dehydrogenase A (in complex with NADH and in the apo form) have been generated to enable structure-based design of novel inhibitors competing with pyruvate and NADH. The structural criteria...