NADPH reduction

Dideoxyhexoses. Several bacterial antigenic determinants with the general structure of 3,6-dideoxyhexoses occur in the cell wall of Pasteurella and Salmonella strains. Most of the transformations reported so far occur as cytidine nucleotides (see Table I, References 15, 16, 17, 18, 19). Here, again the first step is the transformation of the cytidine diphospho-linked glucose into its corresponding 4-keto derivative. By at least two distinct steps, requiring NADPH, reduction to several different 3,6-dideoxyhexoses have been reported. One 3,6-dideoxyhexose CDP-tyvelose (3,6-dideoxy-D-arabino hexose) is formed by a specific 2-epimer-ase from CDP-paratose (24). 

The PPC allows the generation of NADPH reduction equivalents required for cell anabolism, and ribose 5-phosphate molecules for the synthesis of nucleic acids. Alternatively, ribose 5-phosphate can also be generated or transformed into fructose 6-phosphate or glyceraldehyde 3-phosphate, providing metabolic flexibility to the cell, in order to balance the fluxes through these pathways. The flux through the PPC is related to the nucleic acid requirements for DNA duplication or RNA transcription, and could probably be controlled by the cell cycle (Wagner, 1997). 

NADPH reductant Second P-P leaving too C-thirty squalene resultant (Three to lose before we re through)... 

The full structures of pyridoxamine and pyridoxal are on p. 1384. The incorporation of ammor. into a-keto-glutarate and the formation of glutamic acid by NADPH reduction of the imine is -p. 1386. The transamination from glutamic acid to pyridoxamine is on p. 1385. We start fr -pyridoxamine, whose structure we abbreviate, and pyruvate. Imine formation (fiiU mechanism pp. 348-50) followed by proton removal and replacement gives a new imine whose hydrolysis (f mechanism on pp. 350-1) gives alanine and pyridoxal. The alanine is a single enantiomer beca.s enzyme-directed protonation occurs on one face of the imine. Pyridoxal is recycled transamination with glutamic acid. 

Wang, S., Huang, H., Moll, J., and Thauer, R.K. (2010) NADPh- reduction with reduced ferredoxin and NADP-F reduction with NADH are coupled via an electron-bifurcating enzyme complex in Clostridium Iduyveri. J. 

The rate of reduction of cytochrome c by the cobalt-substituted analogue of rubredoxin is a factor of 2.25 lower than the rate with rubredoxin itself. Both proteins mediate the reduction of cytochrome c in the presence of NADH and the decrease in the rate is attributed to the decreased efficiency in oxidation of cobalt(ii) compared with iron(ii). Reduction of cytochrome c by NADPH is catalysed by an adrenodoxin reductase-adrenodoxin complex in which the rate-determining step is electron transfer from the flavin (FAD) of the reductase to the FeaS2 centre of adrenodoxin. The pH dependence of the rate shows a pATa of 6.75, with the high-pH form 27.5 times more reactive than the low-pH form. Both NADPH reduction of the complex and cytochrome c oxidation of the complex were faster than the catalytic rate. Catalytic roles of four iron-sulphur centres in trimethylene dihydrogenase and ferredoxin nitrite reductase have also been examined. Synthetic analogues of four iron ferredoxins have also attracted much attention. - ... 

The enzyme dihydrofolate reductase (DHFR) catalyzes the nicotinamide adenine dinucleotide phosphate (NADPH) reduction of folate to dihydrofolate and tetrahydrofolate, the class of cofactors used in the biosynthesis of thymidylate and hence DNA. Inhibition of DHFR prevents cell growth and kills cells, so... 

A hemithioacetal intermediate formed by the first NADPH reduction... 

Figure 3. Plot of the [NADP ]/[NADP + NADPH] ratio rfraction NADP ) vs. time for a sealed vial containing NADPH (initial concentration 250 fiM) in HEPES/NaCl buffer at pH 7.5 showing the effects of different metallotexaphyrins (12.5 pM initial concentration after dilution ofMGd (I), MLu (2), Y-Tex (3), and Dy Tex (4)) on the rate of NADPH reduction.

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