CU(II)-dependent inactivation of Mn-catalase by hydroxylamine

Hydroxylamine is a strong inhibitor of the Mn-catalase of Lactobacillus plantarum in the presence of hydrogen peroxide [Kono, Y., and Fridovich, I. (1983) J. Biol. Chem. 258, 13646-13648]. In the presence of CuCl2 the Mn-catalase was rapidly inactivated by hydroxylamine without the addition of hydrogen peroxide. FeSO4 and MnCl2 were approximately 10% and 4% as effective as was CuCl2. Under anaerobic conditions, the inactivation did not occur. The chelating agents such as EDTA and histidine completely prevent the inactivation. These results indicate that the hydrogen peroxide produced during the autooxidation of hydroxylamine catalyzed by CuCl2 participates in the CuCl2-dependent inactivation by hydroxylamine.