Abstract
The inhibitory effect of 8-hydroxyquinoline on the amine oxidase [monoamine: oxygen oxidoreductase (deaminating), EC 1. 4. 3. 4] from Aspergillus niger was analyzed on the basis of data which were obtained by the overall reaction kinetics and also by the “flow” method. It was confirmed that 8-hydroxyquinoline inhibited the transamination step non-competitively, but did not inhibit the oxidative reaction of the pyridoxamine phosphate (PMP) form with molecular oxygen. The following reaction scheme for the mode of inhibition of the amine oxidase by 8-hydroxyquinoline was proposed:_??_
where EL stands for the pyridoxal phosphate (PLP) form of the amine oxidase (enzyme unit based on PLP), EM for the PMP form and X and Y for intermediates in the reactions. EL1 and XI are a PLP form-inhibitor complex and an intermediate (X)-inhibitor complex(es), ** respectively.
