Kinetics of the reversible tight-binding inhibition of pig liver catechol-O-methyltransferase by [2-(3,4-dihydroxy-2- nitrophenyl)vinyl]phenyl ketone.
The inactivation of partially purified pig liver catechol-O-methyltransferase (COMT) by [2-(3,4-dihydroxy-2-nitrophenyl)vinyl]phenylketone has been studied. The results demonstrated that COMT is inhibited in a reversible tight-binding fashion with an apparent Ki of 0.2 microM. IC50 values were determined at different concentrations of both substrates of the enzymatic reaction, pyrocatechol and S-adenosyl-L-methionine (AdoMet). The plot of IC50 versus pyrocatechol concentration gave a straight line, suggesting competitive inhibition. However the nitrocatechol derivative showed an uncompetitive inhibition pattern when measured as a function of AdoMet concentration.
Pérez
R A
RA
Instituto de Quîmica Orgânica General del CSIC, Madrid, Spain.
Fernández-Alvarez
E
E
Nieto
O
O
Piedrafita
F J
FJ
D000818:Animals; D002394:Catechol O-Methyltransferase / Q000378:metabolism; D065098:Catechol O-Methyltransferase Inhibitors; D008099:Liver / Q000201:enzymology; D013329:Structure-Activity Relationship; D013552:Swine; D014753:Vinyl Compounds / Q000494:pharmacology*
C093779:(2-(3,4-dihydroxy-2-nitrophenyl)vinyl)phenyl ketone; D065098:Catechol O-Methyltransferase Inhibitors; D014753:Vinyl Compounds; D002394:Catechol O-Methyltransferase