The effect of debrisoquin on MAO A and MAO B activities.
To examine the mode of action of debrisoquin (DEB), we studied the effect of this drug in vitro on MAO A and MAO B enzyme activities. DEB was shown to be a competitive inhibitor of highly purified human MAO A and MAO B enzyme activities. DEB inhibited placental MAO A with a Ki value of 0.5 microM and liver MAO B with a Ki value of 8.8 microM, 18-fold greater effect on the A form. Kynuramine was used as substrate for both enzymes. Additional studies using a dilution technique showed that DEB was a reversible inhibitor of both forms of the enzyme. The results of this study show that DEB is a potent competitive and reversible inhibitor of both MAO A and MAO B enzymes.
Javors
M A
MA
Department of Psychiatry, University of Texas Health Science Center, San Antonio 78284.
Bembenek
M E
ME
Bowden
C L
CL
Abell
C W
CW
Maas
J W
JW
D001679:Biogenic Amines / Q000378:metabolism; D003647:Debrisoquin / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology*; D007700:Kinetics; D007735:Kynuramine / Q000378:metabolism; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology*; D010920:Placenta / Q000201:enzymology; D011247:Pregnancy
D001679:Biogenic Amines; D007546:Isoquinolines; D008996:Monoamine Oxidase Inhibitors; D007735:Kynuramine; D003647:Debrisoquin