Open AccessThe Reversible Inactivation of Rat‐Liver Arginase at Low pH
Author(s) -
Hosoyama Yoshiyuki
Publication year - 1972
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1972.tb01809.x
Subject(s) - chemistry , enzyme , arginase , dissociation (chemistry) , denaturation (fissile materials) , kinetics , arginine , biochemistry , limiting , incubation , chromatography , amino acid , nuclear chemistry , organic chemistry , mechanical engineering , physics , quantum mechanics , engineering
1 Rat liver arginase ( l ‐arginine amidinohydrolase) is inactivated by treatment with acid at 0 °C. 2 The inactivated or denatured enzyme can readily have its catalytic activity restored by incubation at 37 °C in neutral buffer. The amount of reactivation that occurrs depends on the Mn 2+ ion concentration in the renaturation medium. The rate of renaturation also depends on Mn 2 . 3 Disc gel electrophoresis shows that dissociation into subunits occurrs by acid denaturation, the subunits having molecular weights of about 64000 and 32000, at pH 4, and 2 respectively. 4 The renaturation process is temperature dependent and shows first‐order kinetics. Δ H and Δ S for renaturation are 6.0 kcal/mol and – 29.8 cal/K, respectively, at 37 °C. 5 Some annealing process is important for renaturation and it may be a rate‐limiting process which makes the renaturation process an apparently first‐order reaction. 6 The renatured enzyme has the same optimum pH and K m as the native enzyme but loses its original activity in the neutral pH region.