Document Detail

CYP98A3 from Arabidopsis thaliana is a 3'-hydroxylase of phenolic esters, a missing link in the phenylpropanoid pathway.
MedLine Citation:
PMID:  11429408     Owner:  NLM     Status:  MEDLINE    
The 4- and 5-hydroxylations of phenolic compounds in plants are catalyzed by cytochrome P450 enzymes. The 3-hydroxylation step leading to the formation of caffeic acid from p-coumaric acid remained elusive, however, alternatively described as a phenol oxidase, a dioxygenase, or a P450 enzyme, with no decisive evidence for the involvement of any in the reaction in planta. In this study, we show that the gene encoding CYP98A3, which was the best possible P450 candidate for a 3-hydroxylase in the Arabidopsis genome, is highly expressed in inflorescence stems and wounded tissues. Recombinant CYP98A3 expressed in yeast did not metabolize free p-coumaric acid or its glucose or CoA esters, p-coumaraldehyde, or p-coumaryl alcohol, but very actively converted the 5-O-shikimate and 5-O-d-quinate esters of trans-p-coumaric acid into the corresponding caffeic acid conjugates. The shikimate ester was converted four times faster than the quinate derivative. Antibodies directed against recombinant CYP98A3 specifically revealed differentiating vascular tissues in stem and root. Taken together, these data show that CYP98A3 catalyzes the synthesis of chlorogenic acid and very likely also the 3-hydroxylation of lignin monomers. This hydroxylation occurs on depsides, the function of which was so far not understood, revealing an additional and unexpected level of networking in lignin biosynthesis.
G Schoch; S Goepfert; M Morant; A Hehn; D Meyer; P Ullmann; D Werck-Reichhart
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2001-06-27
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  276     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2001 Sep 
Date Detail:
Created Date:  2001-09-24     Completed Date:  2001-11-01     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  36566-74     Citation Subset:  IM    
Department of Plant Stress Response, Institute of Plant Molecular Biology, CNRS UPR 2357, 28 rue Goethe, F-67083 Strasbourg Cedex, France.
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MeSH Terms
Arabidopsis / enzymology*
Arabidopsis Proteins
Cell Line
Chromatography, High Pressure Liquid
Coumaric Acids / chemistry*,  metabolism,  pharmacology
Cytochrome P-450 Enzyme System / chemistry*,  metabolism
DNA, Complementary / metabolism
Evolution, Molecular
Free Radical Scavengers / chemistry,  metabolism,  pharmacology
Lignin / biosynthesis*
Mixed Function Oxygenases / chemistry*,  metabolism
Models, Chemical
Protein Binding
Recombinant Proteins / chemistry,  metabolism
Substrate Specificity
Time Factors
Tissue Distribution
Reg. No./Substance:
0/Arabidopsis Proteins; 0/Coumaric Acids; 0/DNA, Complementary; 0/Free Radical Scavengers; 0/Recombinant Proteins; 7400-08-0/4-coumaric acid; 9005-53-2/Lignin; 9035-51-2/Cytochrome P-450 Enzyme System; EC 1.-/Mixed Function Oxygenases; EC 1.14.-/CYP98A3 protein, Arabidopsis; EC 1.14.-/cytochrome P-450 CYP98A1 (Sorghum bicolor)

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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