Inhibition of diamine oxidase from porcine kidney by pentamidine and other aminoguanidine compounds.
1. Three bisguanidine compounds (those of pentamidine, streptidine and phenformin) were compared for their in vitro inhibitory capacity on diamine oxidase activity (EC 1.4.3.6), the first enzyme of putrescine degradation. 2. Pentamidine was the most potent inhibitor, and phenformine the weaker. Two and a half micromoles of pentamidine was enough to reduce the enzyme activity by 50%, while streptidine and phenformin produced the same effect at concentrations greater than 0.90 and 4 mM, respectively. 3. Pentamidine, streptidine and phenformin appeared to be non-competitive inhibitors, and the Ki values calculated by a Dixon plot were 3 microM, 0.95 mM and 4 mM, respectively.
Cubría
J C
JC
Departamento de Fisiología, Farmacología y Toxicología, Facultad de Veterinaria, Universidad de León, Spain.
Ordóñez
D
D
Alvarez-Bujidos
M L
ML
Negro
A
A
Ortíz
A I
AI
D006631:Amine Oxidase (Copper-Containing) / Q000037:antagonists & inhibitors*; D000818:Animals; D006146:Guanidines / Q000494:pharmacology*; D006595:Hexosamines / Q000494:pharmacology*; D007668:Kidney / Q000201:enzymology*; D007700:Kinetics; D010419:Pentamidine / Q000494:pharmacology*; D010629:Phenformin / Q000494:pharmacology*; D013552:Swine
D006146:Guanidines; D006595:Hexosamines; D010419:Pentamidine; D010629:Phenformin; C005733:streptidine; D006631:Amine Oxidase (Copper-Containing)