Cation dependent O-methyltransferases from rice |
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Authors: | Yoon Jung Lee Bong Gyu Kim Youhoon Chong Yoongho Lim Joong-Hoon Ahn |
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Institution: | (1) Department of Bioscience and Biotechnology, Bio/Molecular Informatics Center, Konkuk University, Seoul, 143-701, South Korea |
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Abstract: | Two lower molecular mass OMT genes (ROMT-15 and -17) were cloned from rice and expressed in Escherichia coli as glutathione S-transferase fusion proteins. ROMT-15 and -17 metabolized caffeoyl-CoA, flavones and flavonols containing two vicinal hydroxyl
groups, although they exhibited different substrate specificities. The position of methylation in both luteolin and quercetin
was determined to be the 3′ hydroxyl group and myricetin and tricetin were methylated not only at 3′ but also at 5′ hydroxyl
groups. ROMT-15 and -17 are cation-dependent and mutation of the predicted metal binding sites resulted in the loss of the
enzyme activity, indicating that the metal ion has a critical role in the enzymatic methylation. |
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Keywords: | Caffeoyl-CoA Flavonoid O-methyltransferase Oryza sativa |
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