Na(+) is the second major coupling ion at membranes after protons, and many pathogenic bacteria use the sodium-motive force to their advantage. A prominent example is Vibrio cholerae, which relies on the Na(+)-pumping NADH:quinone oxidoreductase (Na(+)-NQR) as the first complex in its respiratory chain. The Na(+)-NQR is a multisubunit, membrane-embedded NADH dehydrogenase that oxidizes NADH and...

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...

The chain oxidation of glyceraldehyde-3-phosphate dehydrogenase *NADH by perhydroxyl radicals and propagated by molecular oxygen was studied by the xanthine-xanthine oxidase system, ‘OCo y-ray, and pulse radiolysis. The chain length, amount of NADH oxidized per HOz generated, increases with increasing acidity of the medium and reaches a value of 73 at pH 5.0. The rate constant for the oxidati...

The subunit locations of the five enzymes associated with the fatty acid oxidation complex from Escherichia coli were studied by immunotitration and chemical modification. Antibodies raised against the purified complex caused the parallel inhibitions of enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase, while slightly stimulating 3-ketoacyl-CoA thiolase. All five component enzymes of t...

Protein phosphorylation is crucial for regulating synaptic transmission. We describe a novel mechanism for the phosphorylation of the GABA(A) receptor, which mediates fast inhibition in the brain. A protein copurified and coimmunoprecipitated with the phosphorylated receptor alpha1 subunit; this receptor-associated protein was identified by purification and microsequencing as the key glycolytic...

1. The midpoint potentials of the various iron-sulphur centres in Site I were determined at different pH values by the technique of redox potentiometry. An interesting feature is the pH-dependence of Centre N-2, the highest potential component of the NADH dehydrogenase segment of the respiratory chain. 2. The apparent midpoint potentials of Centre N-2 (NADH dehydrogenase) and S-1 (succinate deh...