An enzyme that catalyzes the reversible hpdroxylation of nicotinic acid to 6-hydroxynicotinic acid has been purified from extracts of a nicotinic acid-fermenting clostridium. The enzyme appears to be a flavin adenine dinucleotidecontaining non-heme iron protein and utilizes triphosphopyridine nucleotide as the ultimate electron acceptor. The purified enzyme also exhibits reduced triphosphopyrid...

DT diaphorase was purified to homogeneity from rat liver and characterized. The molecular weight of the enzyme was calculated to be 5.0 h 0.06 x lo4 from sedimentation equilibrium experiments and to be 4.8 x IO4 by thin layer gel filtration method using Sephadex G-200. The identity of FAD as a prosthetic group was confirmed by o-amino acid oxidase test. It was found that 1 mole of FAD was prese...

The aromatic amines 2-aminofluorene (2AF), 2-acetylaminofluorene, and 2-aminoanthracene, and the heterocyclic amines 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, and 3-amino-1-methyl-SH-pyrido[4,3-b]indole (Trp-P-2) were activated by rat liver cytosolic fractions to form mutagenic metabolites in Salmonella typhimurium strains TA98, TA98NR, and TA98/...

The effect of cupric ions on the activity, fluorescence, and absorbance, and on the sulfhydryl and flavin adenine dinucleotide contents, of lipoyl dehydrogenase has been examined. The changes take place in two phases during the reaction of the enzyme with copper ions. In the first phase, the lipoic activity of the enzyme decreases to about 10% of its initial value, while its diaphorase activity...

Electron mediation between NAD-dependent enzymes using quinone moieties typically requires the use of a diaphorase as an intermediary enzyme. The ability for a naphthoquinone redox polymer to independently oxidize enzymatically-generated NADH is demonstrated for application to glucose/O2 enzymatic fuel cells.