| O-Methylation of benzaldehyde derivatives by "lignin specific" caffeic acid 3-O-methyltransferase. | |
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MedLine Citation:
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PMID: 15081283 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Although S-adenosyl-l-methionine (SAM) dependent caffeic acid/5-hydroxyferulic acid 3/5-O-methyltransferase (COMT) is one of the key enzymes in lignin biosynthesis, the present work demonstrates that alfalfa COMT methylates benzaldehyde derivatives more efficiently than lignin pathway intermediates. 3,4-Dihydroxy, 5-methoxybenzaldehyde and protocatechuic aldehyde were the best in vitro substrates for OMT activity in extracts from developing alfalfa stems, and these compounds were preferred over lignin pathway intermediates for 3-O-methylation by recombinant alfalfa COMT expressed in Escherichia coli. OMT activity with benzaldehydes was strongly reduced in extracts from stems of transgenic alfalfa down-regulated in COMT. However, although COMT down-regulation drastically affects lignin composition, it does not appear to significantly impact metabolism of benzaldehyde derivatives in alfalfa. Structurally designed site-directed mutants of COMT showed altered relative substrate preferences for lignin precursors and benzaldehyde derivatives. Taken together, these results indicate that COMT may have more than one role in phenylpropanoid metabolism (but probably not in alfalfa), and that engineered COMT enzymes could be useful for metabolic engineering of both lignin and benzaldehyde-derived flavors and fragrances. |
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Authors:
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Parvathi Kota; Dianjing Guo; Chloe Zubieta; Joe Noel; Richard A Dixon |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Phytochemistry Volume: 65 ISSN: 0031-9422 ISO Abbreviation: Phytochemistry Publication Date: 2004 Apr |
Date Detail:
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Created Date: 2004-04-14 Completed Date: 2004-07-08 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0151434 Medline TA: Phytochemistry Country: United States |
Other Details:
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Languages: eng Pagination: 837-46 Citation Subset: IM |
Affiliation:
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Plant Biology Division, Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Amino Acid Substitution Benzaldehydes / chemistry, metabolism* Carbon Radioisotopes Down-Regulation Hydroxybenzoic Acids / chemistry, metabolism Kinetics Lignin / metabolism* Medicago sativa / enzymology, genetics Methylation Methyltransferases / genetics, metabolism* Phenols / chemistry, metabolism Plant Stems / enzymology Plants, Genetically Modified / enzymology Recombinant Proteins / genetics, metabolism S-Adenosylmethionine / metabolism Substrate Specificity |
| Chemical | |
Reg. No./Substance:
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0/Benzaldehydes; 0/Carbon Radioisotopes; 0/Hydroxybenzoic Acids; 0/Phenols; 0/Recombinant Proteins; 29908-03-0/S-Adenosylmethionine; 9005-53-2/Lignin; 99-50-3/protocatechuic acid; EC 2.1.1.-/Methyltransferases; EC 2.1.1.68/caffeate O-methyltransferase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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