Non-chelating inhibition of the H101N variant of human liver arginase by EDTA.
Recombinant wild-type human liver arginase (EC 3.5.3.1) expressed in Escherichia coli was markedly resistant to inhibition by ethylene diamine tetraacetic acid (EDTA). In contrast, half and fully activated species of the H101N variant were totally inactive in the presence of approximately 1 mM EDTA. Dilution of inhibited species in metal-free buffer lead to a time dependent recovery of activity, even when measured in the absence of added Mn2+. The inhibition was mixed type, with predominance of a competitive component (Kii=0.31 mM; Kis=0.022 mM). The structurally related N,N,N',N'-tetramethylethylenediamine was not inhibitory, indicating the importance of the carboxyl groups in EDTA inhibition. We conclude that EDTA inhibition of H101N arginase is not due to interaction with a weakly bound Mn2+ or chelation of essential metal ions.
Departamento de Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile. ncarvaja@udec.cl
Nelson
N
Carvajal
María S
MS
Orellana
Jessica
J
Bórquez
Elena
E
Uribe
Vasthi
V
López
Mónica
M
Salas
D001119:Arginase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D002614:Chelating Agents / Q000378:metabolism / Q000494:pharmacology; D004492:Edetic Acid / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D007477:Ions / Q000378:metabolism; D007527:Isoenzymes / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D008345:Manganese / Q000378:metabolism; D008670:Metals / Q000378:metabolism; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
D002614:Chelating Agents; D007477:Ions; D007527:Isoenzymes; D008670:Metals; D011994:Recombinant Proteins; D008345:Manganese; D004492:Edetic Acid; D001119:Arginase