McFaul S J, Lin H, Everse J
Proc Soc Exp Biol Med. 1986 Nov;183(2):244-9. doi: 10.3181/00379727-183-42413.
The kinetics of the cytolytic activity expressed by lactoperoxidase and horseradish peroxidase toward erythrocytes in the presence of H2O2 and iodide have been investigated at physiological pH. The action of both enzymes was found to be very similar with respect to their kinetic mechanisms. Both enzymes showed saturation kinetics at higher enzyme concentrations under conditions where substrate concentrations were not limiting. Optimal concentrations of H2O2 and iodide were found to be 40 and 25 microM, respectively, for both enzymes. Higher concentrations of H2O2 inhibited the cytolytic activity. The pH dependence of the cytolytic reaction is also very similar for both enzymes, showing maximal activity at about pH 6.3. Moreover, the cytolytic activities of both enzymes were inhibited by tyrosine, tryptophan, cysteine, and to a lesser extent by histidine. We conclude from these data that the mechanisms of horseradish peroxidase and lactoperoxidase in promoting the lysis of erythrocytes are closely related if not identical.
在生理pH值条件下，研究了乳过氧化物酶和辣根过氧化物酶在过氧化氢和碘化物存在时对红细胞的溶细胞活性动力学。发现两种酶在动力学机制方面非常相似。在底物浓度不限制的条件下，两种酶在较高酶浓度时均表现出饱和动力学。两种酶的过氧化氢和碘化物最佳浓度分别为40 microM和25 microM。较高浓度的过氧化氢会抑制溶细胞活性。两种酶的溶细胞反应对pH的依赖性也非常相似，在约pH 6.3时表现出最大活性。此外，酪氨酸、色氨酸、半胱氨酸会抑制两种酶的溶细胞活性，组氨酸的抑制作用较小。从这些数据我们得出结论，辣根过氧化物酶和乳过氧化物酶促进红细胞裂解的机制即使不完全相同也密切相关。
