Determination of S-Catechol-O-Methyltransferase Activity in Rat Tissues Using High-Performance Liquid Chromatography with Electrochemical Detection

A high-performance liquid chromatography with electrochemical detection (HPLC-ECD) method was developed to determine the activity of S-catechol-O-methyltransferase (COMT) in rat tissues including the liver, kidney, lung ,spleen and brain. The 3,4-dihydroxybenzoic acid was used as the substrate for S-COMT in rat tissues. After incubated with different tissues, the product 4-hydroxy-3-methoxybenzoic acid was formed from the substrate and separated to measure the COMT activity. The analysis was performed on a Agilent C8 column (5 mum, 150><4.6 mm) at 550 mV potential. The mobile phase was a mixture of methanol and 0.1 M Na₂HPO₄(pH=3.3) containing 0.13 mM ethylenediamine tetraacetic acid (v/v, 14/86) with a flow rate of 1 ml/min. This approach was used to study S-COMT activity in vitro from various tissues.