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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
10
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pubmed:dateCreated |
1980-7-22
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pubmed:abstractText |
N-t-Butyloxycarbonyl-gamma-L-glutaminyl-2-bromo-4-hydroxybenzene alpha-benzyl ester was synthesized as a precursor to gamma-L-glutaminyl-4-hydroxy[2-3H]benzene. With this labeled compound and the previously synthesized gamma-L-glutaminyl-4-hydroxy[3,5-3H]benzene, the stoichiometry of ring substitution was determined for the tyrosinase-catalyzed metabolic pathway of Agaricus bisporus. In this pathway, gamma-L-glutaminyl-4-hydroxybenzene is hydroxylated to gamma-L-glutaminyl-3,4-dihydroxybenzene which is oxidized to gamma-L-glutaminyl-3,4-benzoquinone and a compound of previously unknown structure, "490." The results indicated that the "490" quinone was derived from gamma-L-glutaminyl-3,4-benzoquinone without further ring substitution. A base-catalyzed, nonenzymatic reaction of gamma-L-glutaminyl-3,4-benzoquinone was observed which yielded a compound with a 490 nm chromophore. gamma-Glutamyl transpeptidase cleavage of gamma-L-glutaminyl-3,4-dihydroxybenzene led to the release of 4-aminocatechol which air-oxidized to a compound with identical spectral properties to "490." The structure of "490" was thus determined to be 2-hydroxy-4-imino-2,5-cyclohexadiene-1-one(2-hydroxy-4-iminoquinone). The tyrosinase-catalyzed hydroxylation of gamma-L-glutaminyl-4-hydroxybenzene was found to be optimal at pH 8.0, while the enzymatic oxidation of gamma-L-glutaminyl-3,4-dihydroxybenzene was optimal at pH 6.0.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Catechol Oxidase,
http://linkedlifedata.com/resource/pubmed/chemical/Glutamine,
http://linkedlifedata.com/resource/pubmed/chemical/Mixed Function Oxygenases,
http://linkedlifedata.com/resource/pubmed/chemical/Monophenol Monooxygenase,
http://linkedlifedata.com/resource/pubmed/chemical/Oxidoreductases,
http://linkedlifedata.com/resource/pubmed/chemical/Phenols,
http://linkedlifedata.com/resource/pubmed/chemical/gamma-Glutamyltransferase
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pubmed:status |
MEDLINE
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pubmed:month |
May
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
25
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pubmed:volume |
255
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
4766-71
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:6102990-Agaricales,
pubmed-meshheading:6102990-Catechol Oxidase,
pubmed-meshheading:6102990-Glutamine,
pubmed-meshheading:6102990-Mixed Function Oxygenases,
pubmed-meshheading:6102990-Monophenol Monooxygenase,
pubmed-meshheading:6102990-Oxidoreductases,
pubmed-meshheading:6102990-Phenols,
pubmed-meshheading:6102990-Spectrophotometry,
pubmed-meshheading:6102990-gamma-Glutamyltransferase
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pubmed:year |
1980
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pubmed:articleTitle |
The metabolic pathway catalyzed by the tyrosinase of Agaricus bisporus.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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