Van Duijn M M, Buijs J T, Van der Zee J, Van den Broek P J
Sylvius Laboratory, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands.
Protoplasma. 2001;217(1-3):94-100. doi: 10.1007/BF01289418.
Erythrocytes contain a plasma membrane redox system that can reduce extracellular ascorbate radicals by using intracellular ascorbate as an electron donor. In this study, the hypothesis was tested that cytochrome b561 was a component of this system. Spectroscopic analysis of erythrocyte membrane preparations revealed the presence of cytochrome b5 and hemoglobin but also of a cytochrome with properties similar to cytochrome b561, reducible by ascorbate and insensitive to CO. The presence of cytochrome b561 was studied further by reverse transcriptase-PCR analysis of erythrocyte progenitor cells, reticulocytes. However, no cytochrome b561 mRNA could be found. These results were corroborated by Western blot analysis with an anti-cytochrome b561 serum. No cytochrome b561 protein could be detected in extracts of erythrocyte membranes. It is therefore concluded that erythrocytes do not contain cytochrome b561 in their membranes. The possible involvement of other b-cytochromes in ascorbate-ascorbate free radical oxidoreductase activity is discussed.
红细胞含有一种质膜氧化还原系统，该系统可以利用细胞内的抗坏血酸作为电子供体来还原细胞外的抗坏血酸自由基。在本研究中，对细胞色素b561是该系统的一个组成部分这一假设进行了验证。对红细胞膜制剂的光谱分析表明，存在细胞色素b5和血红蛋白，还存在一种细胞色素，其性质与细胞色素b561相似，可被抗坏血酸还原且对一氧化碳不敏感。通过对红细胞祖细胞（网织红细胞）进行逆转录聚合酶链反应分析，进一步研究了细胞色素b561的存在情况。然而，未发现细胞色素b561 mRNA。用抗细胞色素b561血清进行的蛋白质免疫印迹分析证实了这些结果。在红细胞膜提取物中未检测到细胞色素b561蛋白。因此得出结论，红细胞膜中不含有细胞色素b561。文中还讨论了其他b型细胞色素可能参与抗坏血酸 - 抗坏血酸自由基氧化还原酶活性的情况。
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