Lardinois O M, Rouxhet P G
Unité de Chimie des Interfaces, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
Biochim Biophys Acta. 1996 Dec 5;1298(2):180-90. doi: 10.1016/s0167-4838(96)00130-6.
A study of the azide reaction with bovine liver catalase in presence of hydrogen peroxide has been performed, using conventional UV-visible spectrometry and activity measurements. Compound III and NO-ferrocatalase were the predominant forms of the enzyme observed in air and under nitrogen, respectively. A reaction scheme for peroxidatic degradation of azide by catalase is proposed. Accordingly, accumulation of Compound III is the main factor responsible for the reversible inhibition of 'catalatic' activity by azide, while formation of a complex between native catalase and azide has a negligible effect. Catalase is irreversibly inactivated by prolonged exposure to high levels of H2O2 and azide. The latter involves cleavage of the prosthetic group with liberation of the heme iron. Both in air and under nitrogen, generation of azidyl radicals seems to play a minor role in the irreversible inactivation process.
利用传统的紫外可见光谱法和活性测量方法，对过氧化氢存在下叠氮化物与牛肝过氧化氢酶的反应进行了研究。化合物III和NO-铁过氧化氢酶分别是在空气中和氮气下观察到的该酶的主要形式。提出了过氧化氢酶对叠氮化物进行过氧化物降解的反应方案。因此，化合物III的积累是叠氮化物对“催化”活性产生可逆抑制作用的主要因素，而天然过氧化氢酶与叠氮化物形成复合物的影响可忽略不计。长时间暴露于高浓度的过氧化氢和叠氮化物会使过氧化氢酶不可逆地失活。后者涉及辅基的裂解并释放出血红素铁。在空气中和氮气下，叠氮基自由基的产生似乎在不可逆失活过程中起次要作用。
