Determination of catechol-O-methyltransferase activity in brain tissue by high-performance liquid chromatography with on-line radiochemical detection

✍ Scribed by Erkki Nissinen

• Publisher: Elsevier Science
• Year: 1985
• Tongue: English
• Weight: 426 KB
• Volume: 144
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(85)90112-5

✦ Synopsis

A sensitive assay for catechol-O-methyltransferase (COMT) activity by high-performance liquid chromatography with on-line radiochemical detection was described. The method was based on the measurement of 3H-labeled 3-O- and 4-O-methylated products of the substrate, 3,4-dihydroxybenzoic acid, using S-adenosyl-L-[methyl-3H]methionine as the methyl donor, or the measurement of 14C-labeled 3-O- and 4-O-methylated products of the substrate, [7-14C]dopamine. The reaction products were determined from the incubation mixture after removal of protein by injecting an aliquot into the liquid chromatograph. The detection limit with counting efficiency of 40% was 0.45 pmol 3H-labeled product, and 0.04 pmol 14C-labeled product with 61% counting efficiency. The method is suitable for assaying membrane-bound and soluble COMT activities in the brain tissue and for calculation of meta/para product ratios.