Purification and characterization of the molybdoenzymes nicotinate dehydrogenase and 6-hydroxynicotinate dehydrogenase from Bacillus niacini

Formylmethanofuran dehydrogenases from methanogenic Archaea Substrate specificity, EPR properties and reversible inactivation by cyanide of the molybdenum or tungsten iron‐sulfur proteins

“…Rather, it suggests that the formyl group is dehydrogenated while still bound to the primary amino group of methanofuran yielding N-carboxymethanofuran as product (reaction b) which should break down non-enzymically to CO, and methanofuran (Ewing et al, 1980) : 0 R Reaction (b) indicates that formylmethanofuran dehydrogenase belongs to the group of molybdenum enzymes that catalyze an insertion of an oxygen atom derived from H,O into a C-H bond (Pilato and Stiefel, 1993). Enzymes belonging to this group are xanthine dehydrogenases and xanthine oxidases (Bray, 1988;Wootton et al, 1991), molybdenum-containing formate dehydrogenases (Adams and Mortenson, 1985;Barber et al, 1986;Friedebold and Bowien, 1993), formate-ester dehydrogenase (van Ophem et al, 1992), aldehyde oxidase (Branzoli and Massey, 1974), aldehyde dehydrogenase (Poels et al, 1987), aldehyde oxidoreductase (White et al, 1993), nicotine dehydrogenase (Freudenberg et al, 1988), nicotinate dehydrogenase and 6-hydroxynicotinate dehydrogenase (Nagel and Andreesen, 1990), isonicotinate dehydrogenase and 2-hydroxyisonicotinate dehydrogenase (Kretzer and Andreesen, 1991), quinoline oxidoreductase (Hettrich et al, 1991), quinoline-4-carboxylic acid oxidoreductase (Bauer and Lingens, 19921, quinaldine oxidoreductase (de Beyer and Lingens, 1993), quinaldic acid 4-oxidoreductase (Fetzner and Lingens, 1993), picolinate dehydrogenase (Siegmund et al, 1990), 2-furoyl-coenzyme A dehydrogenase , and pyrimidine oxidase and pyridoxal oxidase (Burgmayer and Stiefel, 1985). Interestingly, one of these enzymes, milk xanthine oxidase, can even catalyze the dehydrogenation of formamide to carbamic acid (Morpeth et al, 1984) which is a reaction also catalyzed by formylrnethanofuran dehydrogenase.…”

Lactate Utilization Is Regulated by the FadR-Type Regulator LldR in Pseudomonas aeruginosa

“…The activities of D-iLDH and L-iLDH were determined at 30°C in 1 ml of 50 mM Tris-HCl (pH 7.5), 0.1 mM 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and the crude cell extract. The reaction was started by the addition of 50 mM L-lactate or D-lactate, and the rate of MTT reduction was determined by measuring the absorbance changes at 570 nm (24). One unit was defined as the amount of enzyme that reduced 1.0 mol of MTT per minute under the test conditions.…”

Catabolism of isonicotinate by Mycobacterium sp. INA1: extended description of the pathway and purification of the molybdoenzyme isonicotinate dehydrogenase

“…For unknown reasons, isonicotinate dehydrogenase activity was somewhat unstable, and a decrease in specific activity occurred during the late steps of purification, either during hydrophobic interaction chromatography or during gel permeation chromatography. Several modifications have been considered to account for the inactivation of related enzymes, as has been thoroughly discussed for a nicotinate dehydrogenase (Nagel & Andreesen, 1990).…”