Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.6.99.1 (NADPH-diaphorase)
 3,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

At approximately equimolar concentrations (approximately 70 microM), and in the presence of excess catalase and superoxide dismutase, DCIP, ferricytochrome c and ferricyanide abstracted 21, 6 and 61%, respectively, of the electron equivalents given up by NADPH to the NADPH-O2 oxidoreductase complex derived from phorbol myristate acetate-stimulated human neutrophils. With a 10-fold increase in ferricyanide, all of the electron equivalents given up by NADPH to the oxidoreductase complex were shunted to ferricyanide concomitant with complete inhibition of NADPH-dependent O2 consumption. These results substantiate the existence of intrinsic diaphorase activity associated with the superoxide generating NADPH-O2 oxidoreductase of human neutrophils.
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PMID:Detection of NADPH diaphorase activity associated with human neutrophil NADPH-O2 oxidoreductase activity. 396 5

Plasma membrane oxidoreductases have been described in all cells and use extracellular impermeant electron acceptors (DCIP, Ferricyanide) that are reduced by NADH. They appear to regulate the overall cell activity in response to oxidative stress from the cellular environment. An NADH-DCIP reductase has been described at the plasma membrane of NB41A3, a neuroblastoma cell line (Zurbriggen and Dryer (1993) Biochim. Biophys. Acta 1183, 513-520) whose activation with extracellular impermeant substrates promotes cell growth. Elutriation was performed to separate cells and the various fractions were analysed for enzyme activity on intact cells combined with flow cytometry. These studies showed that the enzyme is mostly induced and activated during the G1 and during the G2/M-phases. These observations were further corroborated with specific inhibitors of the cell cycle. A three-fold increase in enzyme activity was observed in the presence of alpha-amanitin, a specific cell cycle inhibitor of the G1-phase. Taxol, a specific inhibitor of the M-phase, also induces a significant increase in enzyme activity. FACS analysis of taxol -treated and alpha-amanitin-treated cells corroborated these data. The cells have been synchronized and the enzyme activity was measured at different time intervals. An activity increase was observed after ca. 2-3 h, that corresponds to a raise in the M-phase, according to FACS data. Furthermore, NTera-2 cells - a human neuroblastoma cell line that differentiates into fully mature neurones in the presence of retinoic acid - exhibit a 50% decrease in the enzyme activity during the G0-phase upon differentiation, compared to undifferentiated cells. Together the data presented in this paper show that this plasma membrane NADH-diaphorase affects cell growth and differentiation and is strongly modulated at various phases of the cell cycle.
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PMID:The plasma membrane NADH-diaphorase is active during selective phases of the cell cycle in mouse neuroblastoma cell line NB41A3. Its relation to cell growth and differentiation. 870 90