Vernet P, Rigaudiére N, Ghyselinck N, Dufaure J P, Drevet J R
Laboratoire de Biologie Cellulaire, C.N.R.S., URA1940, Université Blaise Pascal, Clermont II, Aubière, France.
Biochem Cell Biol. 1996;74(1):125-31. doi: 10.1139/o96-014.
The complete sequence of the mouse epididymal protein (MEP24) was cloned. It contains a 663 bp open-reading frame that, after conceptual translation, shows extensive identity with proteins belonging to the glutathione peroxidase (GPX) family. However, a major difference between GPX5 (MEP24) and other known GPXs concerns a protein domain known to be critical for GPX function. To find out what could be the physiological function of such a protein in the mouse epididymis, we have used a mammalian expression system to overexpress the GPX5 protein. Cells constitutively expressing the GPX5 protein were generated and assayed for their ability to metabolize regular substrates of GPX enzymes. Data presented here show that the GPX5-expressing cells can metabolize hydrogen peroxide in a manner that is consistent with a peroxidase activity. However, the substrate preference of the GPX5-expressing cells and their apparent insensitivity to a regular inhibitor of GPX enzymes suggest that the GPX5 protein belongs to a particular class of GPX proteins. Involvement of this protein in the physiology of the mouse epididymis is discussed.
小鼠附睾蛋白（MEP24）的完整序列被克隆出来。它包含一个663bp的开放阅读框，经概念性翻译后，与谷胱甘肽过氧化物酶（GPX）家族的蛋白质有广泛的同源性。然而，GPX5（MEP24）与其他已知GPX之间的一个主要差异涉及一个对GPX功能至关重要的蛋白质结构域。为了弄清楚这种蛋白质在小鼠附睾中的生理功能可能是什么，我们使用了哺乳动物表达系统来过量表达GPX5蛋白。构建了组成性表达GPX5蛋白的细胞，并检测它们代谢GPX酶常规底物的能力。此处呈现的数据表明，表达GPX5的细胞能够以与过氧化物酶活性一致的方式代谢过氧化氢。然而，表达GPX5的细胞对底物的偏好以及它们对GPX酶常规抑制剂的明显不敏感性表明，GPX5蛋白属于一类特殊的GPX蛋白。本文讨论了该蛋白在小鼠附睾生理学中的作用。
