Publication Date:
1997-01-17
Description:
The regio- and stereospecificity of bimolecular phenoxy radical coupling reactions, of especial importance in lignin and lignan biosynthesis, are clearly controlled in some manner in vivo; yet in vitro coupling by oxidases, such as laccases, only produce racemic products. In other words, laccases, peroxidases, and comparable oxidases are unable to control regio- or stereospecificity by themselves and thus some other agent must exist. A 78-kilodalton protein has been isolated that, in the presence of an oxidase or one electron oxidant, effects stereoselective bimolecular phenoxy radical coupling in vitro. Itself lacking a catalytically active (oxidative) center, its mechanism of action is presumed to involve capture of E-coniferyl alcohol-derived free-radical intermediates, with consequent stereoselective coupling to give (+)-pinoresinol.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Davin, L B -- Wang, H B -- Crowell, A L -- Bedgar, D L -- Martin, D M -- Sarkanen, S -- Lewis, N G -- New York, N.Y. -- Science. 1997 Jan 17;275(5298):362-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/8994027" target="_blank"〉PubMed〈/a〉
Keywords:
Dimerization
;
Flavin Mononucleotide/metabolism
;
Flavin-Adenine Dinucleotide/metabolism
;
Free Radicals
;
Furans/chemistry/*metabolism
;
Kinetics
;
Laccase
;
Lignans/*biosynthesis/chemistry
;
Molecular Conformation
;
Oxidation-Reduction
;
Oxidoreductases/chemistry/*metabolism
;
Phenols/chemistry/*metabolism
;
Plant Proteins/*metabolism
;
Stereoisomerism
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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