KINETICS OF THE REVERSIBLE TIGHT-BINDING INHIBITION OF PIG-LIVER CATECHOL-O-METHYLTRANSFERASE BY [2,(3,4-DIHYDROXY-2-NITROPHENYL) VINYL]PHENYL KETONE

Authors
PEREZ RA FERNANDEZALVAREZ E NIETO O PIEDRAFITA FJ
Citation
Ra. Perez et al., KINETICS OF THE REVERSIBLE TIGHT-BINDING INHIBITION OF PIG-LIVER CATECHOL-O-METHYLTRANSFERASE BY [2,(3,4-DIHYDROXY-2-NITROPHENYL) VINYL]PHENYL KETONE, Journal of enzyme inhibition, 8(2), 1994, pp. 123-131
Citations number
24
Categorie Soggetti
Biology
Journal title
Journal of enzyme inhibition → ACNP
ISSN journal
87555093
Volume
8
Issue
2
Year of publication
1994
Pages
123 - 131
Database
ISI
SICI code
8755-5093(1994)8:2<123:KOTRTI>2.0.ZU;2-F
Abstract
The inactivation of partially purified pig liver catechol-0-methyltran sferase (COMT) by [2-(3,4-dihydroxy-2-nitrophenyl)vinyl]phenylketone h as been studied. The results demonstrated that COMT is inhibited in a reversible tight-binding fashion with an apparent K(i) of 0.2 muM. IC5 0 values were determined at different concentrations of both substrate s of the enzymatic reaction, pyrocatechol and S-adenosyl-L-methionine (AdoMet). The plot of IC50 versus pyrocatechol concentration gave a st raight line, suggesting competitive inhibition. However the nitrocatec hol derivative showed an uncompetitive inhibition pattern when measure d as a function of AdoMet concentration.