NADPH oxidoreductase

Helfrich, M. et al.. Chlorophylls of the c family absolute configuration and inhibition of NADPH protochlorophylhde oxidoreductase, Biochim. Biophys. Acta, 1605, 97, 2003. 

The subcellular location of PG was studied in cells disrupted by osmotic lysis through formation and disruption of sphaeroplasts from self-induced anaerobically-grown cells. A discontinuous sucrose-density gradient produced four bands labelled I, II, III and IV. Band I included many vesicles and a peak of alkaline phosphatase activity (a vacuolar marker in yeasts), NADPH cytochrome c oxidoreductase activity, an endoplasmic reticulum marker, and... 

Subsequently, proteolytic fragments of the rabbit renal 25-kDa amiloride-binding protein were micro-sequenced and found to have high sequence homology with rat and human NAD(P)H quinone oxidoreductase. Indeed, enzymatic assays revealed that renal brush border membrane vesicles contain significant NADPH quinone oxidoreductase activity. Presumably NAD(P)H quinone oxidoreductase coincidentally binds amiloride analogs with the same rank order as the Na /H exchanger [39]. 

The aerobic reduction of aryl and alkyl carboxylates to the corresponding aldehydes. The reaction involves formation of an acyl-AMP intermediate by reaction of the carboxylic acid with ATP NADPH then reduces this to the aldehyde (Li and Rosazza 1998 He et al. 2004). The oxidoreductase from Nocardia sp. is able to accept a range of substituted benzoic acids, naphthoic acids, and a few heterocyclic carboxylic acids (Li and Rosazza 1997). 

Strobl G, R feicht, H White, F Lottspeich, H Simon (1992) The tungsten-containing aldehyde oxidoreductase from Clostridium thermoaceticum and its complex with a viologen-accepting NADPH oxidoreductase. Biol Chem Hoppe-Seyler il i 123-132. 

Clark DD, JR Allen, SA Ensign (2000) Characterization of five catalytic activities associated with the NADPH 2-ketopropyl-coenzyme M [2-(2-ketopropylthio)ethanesulfonate] oxidoreductase/carboxylase of the Xanthobacter strain Py2 epoxide carboxylase system. Biochemistry 39 1294-1304. 

Oxidoreductases are a family of enzymes that catalyze a number of industrially important reactions, but they often require additional nicotinamide (NADH or NADPH) cofactors which... 

Ketoreductases catalyze the reversible reduction of ketones and oxidation of alcohols using cofactor NADH/NADPH as the reductant or NAD + /NADP+ as oxidant. Alcohol oxidases catalyze the oxidation of alcohols with dioxygen as the oxidant. Both categories of enzymes belong to the oxidoreductase family. In this chapter, the recent advances in the synthetic application of these two categories of enzymes are described. 

The catalytic activity of CYP enzymes requires functional coupling with its redox partners, cytochrome P450 NADPH oxidoreductase (OR) and cytochrome bs. Measurable levels of these two proteins are natively expressed in most cell lines. Therefore, introduction of only the CYP cDNA is generally needed for detectable catalytic activity. However, the levels of expression of the redox partner proteins may not support maximal CYP catalytic activity, and therefore enhancement of OR levels may be desirable. This approach has been used successfully with an adenovirus expression system in LLC-PKi cells [12],... 

The enzyme ferridoxin (Fd) NADP + oxidoreductase accepts the electron from Fd, one at a time, as it proceeds from its oxidized form through a semiquinone intermediate to its fully reduced form. The enzyme then transfers a hydride ion to NADP converting to its reduced state NADPH. Uptake of a proton in the reduction of NADP+ further contributes to the proton gradient across the thylakoid membrane driving ATP synthesis. 

Mammalian thioredoxin reductases are a family of selenium-containing pyridine nucleotide-disulfide oxidoreductases. These enzymes catalyze NADPH-dependent reduction of the redox protein thioredoxin (Trx), which contains a redox-active disulfide and dithiol group and by itself may function as an efficient cytosolic antioxidant [77]. One of the functions of Trx/ thioredoxin reductase system is the NADPH-catalyzed reduction of protein disulfide [78] ... 

The peptide sequences obtained for codeinone reductase aligned well with the amino acid sequences for 6 -deoxychalcone synthase (chalcone reductase) from alfalfa, Glycerrhiza, and soybean. Knowledge of the relative positions of the peptides allowed for a quick RT-PCR based isolation of cDNAs encoding codeinone reductase from P. somniferum. The codeinone reductase isoforms are 53 % identical to chalcone reductase from soybean.25 By sequence comparison, both codeinone reductase and chalcone reductase belong to the aldo/keto reductase family, a group of structurally and functionally related NADPH-dependent oxidoreductases, and thereby possibly arise from primary metabolism. Six alleles encoding codeinone... 

Crespi, C.L. and Miller, V.P. (1997) The R144C change in the CYP2C9 2 allele alters interaction ofthe cytochrome P450 with NADPH cytochrome P450 oxidoreductase. Pharmacogenetics, 7 (3), 203-210. 

Bolscher, B. G. J. M., van Zwieten, R., Kramer, I. M., Weening, R. S., Verhoeven, A. J., Roos, D. (1989). A phosphoprotein of Mr 47,000, defective in autosomal chronic granulomatous disease, copurifies with one of two soluble components required for NADPH 02 oxidoreductase activity in human neutrophils. J. Clin. Invest. 83, 757-63. 

Qrunones can accept one or two electrons to form the semiquinone anion (Q ") and the hydroquinone dianion (Q ). Single-electron reduction of a quinone is catalyzed by flavoenzymes with relatively low substrate selectivity (Kappus, 1986), for instance NADPH cytochrome P-450 reductase (E.C. 1.6.2.3), NADPH cytochrome b5 reductase (E.C. 1.6.2.2), and NADPH ubiquinone oxidoreductase (E.C. 1.6.5.3). The rate of reduction depends on several interrelated chemical properties of a quinone, including the single-electron reduction potential, as well as the number, position, and chemical characteristics of the substituent(s). The flavoenzyme DT-diphorase (NAD(P)H quinone acceptor oxidoreductase E.C. 1.6.99.2) catalyzes the two-electron reduction of a quinone to a hydroquinone. 

This enzyme [EC 1.5.1.24], also referred to as A -(1-l-carboxyethyl)-L-ornithine NADP+ oxidoreductase, reversibly catalyzes the reaction of ornithine with pyruvate and NADPH to produce A -(l-carboxyethyl)ornithine, NADP+, and water. Lysine can also serve as a substrate, acting on A , albeit not as effectively as ornithine. 

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