Time-dependent inhibition of diamine oxidase by carbonyl-group reagents and urea.
1. The behaviour of several carbonyl group reagents and urea as time-dependent inhibitors of both pig kidney and human placental diamine oxidase is described. 2. Plots of log (vt/vo) against time were not linear with these reagents as the usual theories predict. 3. This was particularly the case with aminoguanidine and phenylhydrazine and a thorough study of the effects of these compounds on the human placental diamine oxidase is described. 4. By applying a new theory for time-dependent inhibition, the inhibition of diamine oxidase by aminoguanidine and phenylhydrazine is adequately accounted for. 5. The time-dependent recovery of activity on addition of sodium pyruvate suggested that the compounds used are acting solely as carbonyl group reagents, inhibiting by Schiff-base formation at the active-site carbonyl group.
D006631:Amine Oxidase (Copper-Containing) / Q000037:antagonists & inhibitors*; D000588:Amines / Q000494:pharmacology*; D000818:Animals; D001386:Azides / Q000494:pharmacology*; D005260:Female; D006146:Guanidines / Q000494:pharmacology; D006801:Humans; D006834:Hydrazines / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D006898:Hydroxylamines / Q000494:pharmacology; D007668:Kidney / Q000201:enzymology; D007700:Kinetics; D008433:Mathematics; D010920:Placenta / Q000201:enzymology; D011247:Pregnancy; D012663:Semicarbazides / Q000494:pharmacology; D013552:Swine; D014508:Urea / Q000494:pharmacology*
D000588:Amines; D001386:Azides; D006146:Guanidines; D006834:Hydrazines; D006898:Hydroxylamines; D012663:Semicarbazides; D014508:Urea; D006631:Amine Oxidase (Copper-Containing)