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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
5
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pubmed:dateCreated |
1981-4-24
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pubmed:abstractText |
The enzyme responsible for the respiratory burst in human neutrophils is a membrane-bound oxidase that catalyzes the reduction of oxygen to O2- at the expense of a reduced pyridine nucleotide. We describe further properties of the solubilized oxidase. The rates of O2- production and NADPH consumption are consistent with the stoichiometry: 2 O2 + NADPH leads to 2 O2- + NADP The enzyme is highly specific for oxygen, failing to reduce several artificial electron acceptors including ferricyanide. FAD, an essential cofactor, binds tightly to the enzyme, as indicated by a Km of 61 nM. A requirement for a free --SH group is suggested by a 2-fold increase in activity in the presence of low concentrations of dithiothreitol; the higher dithiothreitol concentrations lead to inhibition. The solubilized enzyme is highly unstable, losing one-half its activity after 1 h at room temperature. Loss of activity is accelerated 2- to 3-fold by salts and EDTA. The substrate analog 2',5'-ADP is similar to other salts in its effect on the inactivation rate. ATP, on the other hand, causes loss of activity in seconds, raising the possibility that ATP is a physiological regulator of the catalytic activity of the enzyme.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
10
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pubmed:volume |
256
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
2321-3
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:7462239-Cations, Divalent,
pubmed-meshheading:7462239-Dithiothreitol,
pubmed-meshheading:7462239-Drug Stability,
pubmed-meshheading:7462239-Electron Transport,
pubmed-meshheading:7462239-Humans,
pubmed-meshheading:7462239-Kinetics,
pubmed-meshheading:7462239-NADH, NADPH Oxidoreductases,
pubmed-meshheading:7462239-NADPH Oxidase,
pubmed-meshheading:7462239-Neutrophils,
pubmed-meshheading:7462239-Substrate Specificity
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pubmed:year |
1981
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pubmed:articleTitle |
The O2--producing enzyme of human neutrophils. Further properties.
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pubmed:publicationType |
Journal Article
|