Assessment of catechol-O-methyltransferase activity and its inhibition in erythrocytes of animals and humans.
A non-radiometric method to measure the catechol-O-methyltransferase (COMT) activity in erythrocytes was modified to increase its sensitivity four-fold as well as its reproducibility and applicability. The method is based on the COMT-mediated O-methylation of 4-(naphtho [1,2-d] thiazol-2-yl) pyrocatechol, the product of which was determined fluorometrically. COMT activities down to less than 1% of those present at baseline could be measured precisely and accurately. The intra- and inter-assay coefficients were below 3 and 5.3%, respectively. Basal COMT activity and the distribution between soluble and membrane-bound COMT was shown to be variable among different species (ten species tested). The applicability of the method was demonstrated by the characterization of COMT activity-time courses in human erythrocytes after oral administration of the COMT inhibitor tolcapone. The assay developed will be useful in the rapid screening and clinical development of new COMT inhibitors.
Zürcher
G
G
Department of Preclinical Research, F. Hoffmann-La Roche Ltd., Basel, Switzerland.
Da Prada
M
M
Dingemanse
J
J
D000818:Animals; D001577:Benzophenones / Q000494:pharmacology; D002394:Catechol O-Methyltransferase / Q000097:blood*; D065098:Catechol O-Methyltransferase Inhibitors; D002645:Chickens; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000706:statistics & numerical data; D004285:Dogs; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004912:Erythrocytes / Q000201:enzymology*; D005260:Female; D006801:Humans; D008251:Macaca; D008745:Methylation; D009596:Nitrophenols; D011817:Rabbits; D012016:Reference Values; D000077867:Tolcapone
D001577:Benzophenones; D065098:Catechol O-Methyltransferase Inhibitors; D004791:Enzyme Inhibitors; D009596:Nitrophenols; D000077867:Tolcapone; D002394:Catechol O-Methyltransferase