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Improved assay of reaction products to quantitate catechol-O-methyltransferase activity by high-performance liquid
I Reenilä1, P Tuomainen, P T Männistö
1Department of Pharmacology and Toxicology, University of Helsinki, Finland.
Abstract:
We applied coulometric detection (three electrochemical electrodes in series) to quantitate vanillic acid and isovanillic acid using reversed-phase HPLC. The formation of these reaction products from dihydroxybenzoic acid was used as a precise and reproducible measure of catechol-O-methyltransferase (COMT) activity in striatal homogenates and recombinant membrane-bound COMT protein. This detection system has a higher sensitivity (0.5 pmol per injection) than a single-cell amperometric detection. As in a previous method, the deproteinized supernatants of the COMT assay could be injected directly onto the HPLC system allowing the handling of a large number of samples in one day.