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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
3
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pubmed:dateCreated |
1984-3-16
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pubmed:abstractText |
The flavin prosthetic group (FAD) of the aromatic hydroxylases melilotate hydroxylase (EC 1.14.13.4) and phenol hydroxylase (EC 1.14.13.7) was replaced by 1-deaza-FAD (carbon substituted for nitrogen at position 1). Neither modified enzyme could hydroxylate its substrate, both catalyzed the oxidation of NAD(P)H to NAD(P)+ and H2O2. The rate of the reduction of the enzymes by NAD(P)H was increased by the binding of substrate. Both enzymes formed a detectable flavin C(4a) hydroperoxide intermediate upon reaction of the reduced enzyme-substrate complex with oxygen. Reduced 1-deaza-FAD phenol hydroxylase also showed a detectable C(4a) hydroperoxide intermediate when reacted with oxygen in the absence of substrate. The C(4a) hydroperoxide of 1-deaza-FAD phenol hydroxylase, in the absence of phenol, decayed to an intermediate which showed a perturbed oxidized enzyme spectrum, Eox. This intermediate in turn decayed to give the original oxidized enzyme. In the presence of phenol, a second oxidized species with a perturbed spectrum, intermediate X, was apparent after formation of the flavin C(4a) hydroperoxide and before Eox formation. Steady state kinetic analysis of 1-deaza-FAD phenol hydroxylase demonstrated that the Eox to Eox conversion was not in the catalytic cycle. During turnover Eox was reduced by NADPH.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/1-deaza-FAD,
http://linkedlifedata.com/resource/pubmed/chemical/Apoenzymes,
http://linkedlifedata.com/resource/pubmed/chemical/Flavin-Adenine Dinucleotide,
http://linkedlifedata.com/resource/pubmed/chemical/Mixed Function Oxygenases,
http://linkedlifedata.com/resource/pubmed/chemical/NAD,
http://linkedlifedata.com/resource/pubmed/chemical/NADP,
http://linkedlifedata.com/resource/pubmed/chemical/melilotate 3-monooxygenase,
http://linkedlifedata.com/resource/pubmed/chemical/phenol 2-monooxygenase
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pubmed:status |
MEDLINE
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pubmed:month |
Feb
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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 |
259
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1532-8
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading | |
pubmed:year |
1984
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pubmed:articleTitle |
Reactions of 1-deaza-FAD-substituted phenol hydroxylase and melilotate hydroxylase.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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