Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.6.3.1 (NADPH oxidase)
 11,281 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cell-free extracts of a streptomycin-bleached strain of Euglena gracilis var. bacillaris have been examined for enzyme systems primarily responsible for the oxidation of reduced pyridine nucelotides. NADH lipoyl dehydrogenase, NADH and NADPH oxidase, NADH and NADPH diaphorase, and NADH and NADPH cytochrome c reductase have been demonstrated. The NADPH-linked enzymes had lower activity rates and were less sensitive to N-ethyl maleimide and p-hydroxymercuribenzoate than their NADH-linked counterparts. NADH cytochrome c reductase was the most sensitive to antimycin A. Michaelis-Menten constants (Km) determined were as follows: NADH diaphorase, 350 muM; NADPH oxidase 150 muM ; NADH lipoyl dehydrogenase, 0.35 muM. Enzyme activities after storage at -5 C indicate that the diaphorases are less labile than the other tested enzymes, and the differential activities of the NADH and NADPH linked enzymes suggest that functionally they may have different roles.
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PMID:Reduced pyridine nucleotide oxidases of Eugena gracilis var. bacillaris. 40 56

Bulk membrane fragments were prepared from cells of Bacillus cereus ATCC 4342 harvested at different stages of growth and sporulation and examined for enzymes involved in electron transport functions. The presence of succinate: DCPIP oxidoreductase (EC 1.3.99.1), succinate: cytochrome c oxidoreductase (EC 1.3.2.1), NADH:DCPIP oxidoreductase (EC 1.6.99.1), NADH:cytochrome c oxidoreductase (EC 1.6.2.1), succinate oxidase [succinate: (O(2)) oxidoreductase, EC 1.3.3.1], and NADH oxidase [NADH:(O(2)) oxidoreductase, EC 1.6.3.1] were demonstrated in membrane fragments from vegetative cells, early and late stationary-phase cells, and in cells undergoing sporulation. During the transition from a vegetative cell to a spore, there was a significant increase in the levels of enzymes associated with energy production via the electron transport system. Cytochromes of the a, b, and c type were detected in all membrane preparations; however, there was a marked increase in the level of cytochromes by the end of vegetative growth which remained throughout sporulation; there were no qualitative changes in the cytochromes throughout growth and sporulation. Sporulation was inhibited by cyanide, stressing the significance of the electron transport system. Enzyme activities were partially masked in washed membrane fragments; however, unmasking (stimulation) was achieved by sodium deoxycholate, sodium dodecyl sulfate, or Triton X-100. The degree of enzyme masking was less in vegetative cell membrane fragments than in membranes prepared from stationary-phase or sporulating cells. Results indicate the development of a membrane-bound electron transport system in B. cereus by the end of growth and prior to sporulation, which results in an increased masking of a number of enzymes associated with the terminal respiratory system of the cell.
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PMID:Development of a membrane-bound resiratory system prior to and during sporulation in Bacillus cereus and its relationship to membrane structure. 433 50

Hypoxic pulmonary vasoconstriction (HPV) is a regulatory feature of the pulmonary circulation that ensures consistent matching of perfusion to ventilation in the normal lung. However, under pathophysiological conditions, HPV contributes to the elevated pulmonary arterial pressure inherent to numerous disease states. Consequently, control of HPV is an avenue of potential therapy for such conditions. This review discusses the role of hydrogen peroxide (H(2)O(2)) as an intracellular signal in the pulmonary circulation, concentrating on the potential involvement of H(2)O(2) in HPV and in the control of pulmonary arterial tone. Sites of hypoxic pulmonary arterial H(2)O(2) production include the mitochondrial electron transport chain, a microsomal electron transport chain containing an NADH oxidoreductase and alternatively, a membrane-bound NADPH oxidase. Each of these sources of H(2)O(2) and the effect of hypoxia on the production of reactive oxygen species are considered. The review also discusses the variance in vascular reactivity of H(2)O(2), which is described to elicit both pulmonary arterial vasoconstriction and dilatation at varying concentrations. The redox capabilities of H(2)O(2) are also considered. The relevance of all of these actions of H(2)O(2) are also assessed as potential pharmacological targets for the future development of therapy for lung diseases that are characterised by some degree of HPV and in the pathogenesis of pulmonary diseases in which reactive oxygen species are implicated.
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PMID:Hydrogen peroxide--an intracellular signal in the pulmonary circulation: involvement in hypoxic pulmonary vasoconstriction. 1115 May 95