6.7-Dihydroxycumarin (Aesculetin) als Substrat der Catechol-O-Methyltransferase / 6,7-Dihydroxycoumarin (Aesculetin) as a Substrate for Catediol-O-methyltransferase
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Media type:
E-Article
Title:
6.7-Dihydroxycumarin (Aesculetin) als Substrat der Catechol-O-Methyltransferase / 6,7-Dihydroxycoumarin (Aesculetin) as a Substrate for Catediol-O-methyltransferase
Contributor:
Müller-Enoch, D.;
Seidl, E.;
Thomas, H.
Description:
<jats:p> 6,7-Dihydroxycoumarin (Aesculetin) was found to be a substrate of rat liver Catechol-O-methylfransferase (COMT) (EC 2.1.1.6).</jats:p>
<jats:p> Incubation of this substrate with S-Adenosyl-ʟ-[methyl-<jats:sup>14</jats:sup>C] methionine and/or S-Adenosyl- methionin-hydrogensulfate in the presence of COMT yields the highly fluorescent compounds 7-hydroxy-6-methoxycoumarin (Scopoletin) and 6-hydroxy-7-methoxycoumarin (Isoscopoletin) in the ration of about 2:1. The O-methylated products obtained from Aesculetin were identified after separation by thin layer chromatographpy mainly by the reversed isotope dilution technique.</jats:p>
<jats:p> The fluorescence of the isolated methylethers was proportional to concentration within the range from 10<jats:sup>-5</jats:sup> - 10<jats:sup>-7</jats:sup>M. A reciprocal plot of activity versus substrate concentration gives a K<jats:sub>m </jats:sub>of 1 × 10<jats:sup>-6</jats:sup> M. </jats:p>