Time-dependent inhibition of pea cotyledon diamine oxidase by some hydrazides.
The inhibition of diamine oxidase (EC 1.4.3.6) from pea cotyledons (PDAO) by some hydrazides has been studied. It was found that PDAO is inhibited in a time-dependent manner at pH = 7.0 by the hydrazides of acetic, benzoic, nicotinic, isonicotinic, picolinic and 3,4-dihydro-4-oxophtalazine-1-carboxylic acids, by 1-(carboxymethyl)trimethylammonium chloride hydrazide (Girard's reagent T), 1-(carboxymethyl)pyridinium chloride hydrazide (Girard's reagent P) and oxalic acid dihydrazide. The inhibition was partially reversible. Rate constants for enzyme inactivation were in the range 0.29-1.95 min-1. The hydrazides give apparent noncompetitive inhibition at pH = 7.0, but for isonicotinic hydrazide, this changes to competitive inhibition at pH = 8.0. Apparent inhibition constants (K1APP) for the hydrazides with PDAO are in the range 0.005-1.5 mmol l-1.
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Department of Analytical and Organic Chemistry, Faculty of Science, Palacký University, Olomouc, Czechoslovakia.
Haviger
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A
Kopecná
D
D
Frébort
I
I
D006631:Amine Oxidase (Copper-Containing) / Q000037:antagonists & inhibitors*; D007887:Fabaceae / Q000201:enzymology*; D006834:Hydrazines / Q000494:pharmacology*; D007700:Kinetics; D008956:Models, Chemical; D010946:Plants, Medicinal
D006834:Hydrazines; D006631:Amine Oxidase (Copper-Containing)