Nicotinamide-adenine-dinucleotide hydrogenase

The liberated nicotinamide-adenine-dinucleotide hydrogenase (NADH) has an absorption maxima at 340 nm, whereas lactic acid. NAD+ and pyruvic acid do not absorb at all at this wavelenath. 

Enzymatic reactions UV-visible absorption spectrophotometric determination of enzyme inhibitors is much more popular than that of enzyme activators. Drugs such as neostigmyne, chloropromazine, and cisplatin can be determined by inhibition of soluble or bound enzymes, viz., acetylcholine sterase. Nicotinamide adenine dinucleotide hydrogenase (NADH), and peroxidase, respectively. 

Cassatella, M. A., Hartman, L., Perussia, B., Trinchieri, G. (1989). Tumor necrosis factor and immune interferon synergistically induce cytochrome b.245 heavy-chain gene expression and nicotinamide-adenine dinucleotide phosphate hydrogenase oxidase in human leukemic myeloid cells. J. Clin. Invest. 83,1570-9. 

It is converted to coenzymes, nicotinamide adenine dinucleotide (NAD) or nicotinamide adenine dinucleotide phosphate (NADP). These coenzymes are bound to hydrogenases, function as oxidants by accepting hydrogen and electrons from substrates and become reduced. 

The soluble hydrogenase from the hydrogen-oxidizing bacterium N. opaca is one of a class of hydrogenases that contain flavin and use nicotinamide adenine dinucleotide (NAD) as electron acceptor. The protein consists of four dissimilar subunits and contains approximately four atoms of nickel, one FMN, three [Fe-4S] clusters, one [2Fe-2S] cluster, and up to one [3Fe-xS] cluster (82). Two of the nickel atoms were readily removed by dialysis, in contrast to the nickel in most hydrogenases. The enzyme would only catalyze electron transfer from hydrogen to NAD if cations, of which Ni2+ is the most effective, were added. In the absence of the cations, the enzyme could be separated as... 

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