title: High-performance liquid chromatography-fluorescent assay of catechol-O-methyltransferase activity in rat brain.
abstract: A method to measure catechol- O-methyltransferase (COMT) activity using high performance liquid chromatography-fluorescence detection with norepinephrine (NE) as a natural substrate was optimized for both soluble (S-) and membrane-bound (MB-) COMT activities in rat brain areas, cerebral cortex, cerebellum, hippocampus, brain stem, hypophysis, and hypothalamus. The highest S-COMT activity in Sprague-Dawley rat brain was found in hippocampus. MB-COMT activities in all brain areas were about 3-8 times lower than S-COMT activities. However, considering Vmax/ Km values, specificity constants for NE to S- and MB-COMT contributes mainly to the metabolism of NE in cerebral cortex and cerebellum.
authors.affiliation: Laboratory of Bio-Analytical Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-0033 Tokyo, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Masuda
authors.forename: Makoto
authors.initials: M
authors.lastname: Tsunoda
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Imai
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology*; D002394:Catechol O-Methyltransferase / Q000032:analysis* / Q000378:metabolism; D002462:Cell Membrane / Q000201:enzymology; D002531:Cerebellum / Q000201:enzymology; D002540:Cerebral Cortex / Q000201:enzymology; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D005453:Fluorescence; D006624:Hippocampus / Q000201:enzymology; D062385:Hydroxybenzoates / Q000378:metabolism; D007700:Kinetics; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D013997:Time Factors
chemical_list: D062385:Hydroxybenzoates; D002394:Catechol O-Methyltransferase; D009638:Norepinephrine