Gaetani G F, Ferraris A M, Rolfo M, Mangerini R, Arena S, Kirkman H N
Division of Hematological Oncology, Istituto Nazionale per la Ricerca sul Cancro, University of Genoa, Italy.
Blood. 1996 Feb 15;87(4):1595-9.
Purified enzymes were mixed to form a cell-free system that simulated the conditions for removal of hydrogen peroxide within human erythrocytes. Human glutathione peroxidase disposed of hydrogen peroxide (H2O2) at a rate that was only 17% of the rate at which human catalase simultaneously removed hydrogen peroxide. The relative rates observed were in agreement with the relative rates predicted from the kinetic constants of the two enzymes. These results confirm two earlier studies on intact erythrocytes, which refuted the notion that glutathione peroxidase is the primary enzyme for removal of hydrogen peroxide within erythrocytes. The present findings differ from the results with intact cells, however, in showing that glutathione peroxidase accounts for even less than 50% of the removal of hydrogen peroxide. A means is proposed for calculating the relative contribution of glutathione peroxidase and catalase in other cells and species. The present results raise the possibility that the major function of glutathione peroxidase may be the disposal of organic peroxides rather than the removal of hydrogen peroxide.
将纯化的酶混合以形成一个无细胞系统，该系统模拟了人类红细胞内过氧化氢清除的条件。人类谷胱甘肽过氧化物酶清除过氧化氢（H2O2）的速率仅为人类过氧化氢酶同时清除过氧化氢速率的17%。观察到的相对速率与根据这两种酶的动力学常数预测的相对速率一致。这些结果证实了两项早期对完整红细胞的研究，这两项研究驳斥了谷胱甘肽过氧化物酶是红细胞内清除过氧化氢的主要酶的观点。然而，目前的研究结果与完整细胞的结果不同，表明谷胱甘肽过氧化物酶在过氧化氢清除中所占比例甚至不到50%。提出了一种计算谷胱甘肽过氧化物酶和过氧化氢酶在其他细胞和物种中的相对贡献的方法。目前的结果增加了谷胱甘肽过氧化物酶的主要功能可能是处理有机过氧化物而不是清除过氧化氢的可能性。
