Arienti G, Carlini E, Polci A, Cosmi E V, Palmerini C A
Istituto di Biochimica e Chimica Medica, Università degli Studi di Perugia, Via del Giochetto, Perugia, 06127, USA.
Arch Biochem Biophys. 1998 Oct 15;358(2):391-5. doi: 10.1006/abbi.1998.0876.
Prostasomes are organelles of prostatic origin found in human semen. Their average diameter is about 150 nm and they appear as a lipoprotein membrane surrounding less organized material. Their lipid composition is peculiar, having much cholesterol and sphingomyelin. On the other hand, many of their proteins possess catalytic activity and are involved in the immune response. In previous work, we have shown that prostasomes may fuse to sperm at slightly acidic pH values, thereby modifying the composition of the sperm plasma membrane. In this paper, we examine the fatty acid pattern of prostasome lipid and find that it is completely different from that of sperm membrane lipid. Polyunsaturated phosphatidylcholines, common in sperm membrane, are rare in prostasome. Therefore, the fusion between prostasomes and sperm should stabilize sperm plasma membrane by enriching it in cholesterol, sphingomyelin, and saturated glycerophospholipid. This would prevent the untimely occurrence of the acrosome reaction.
前列腺小体是存在于人类精液中的前列腺源细胞器。它们的平均直径约为150纳米，呈现为围绕着组织较松散物质的脂蛋白膜。它们的脂质组成独特，含有大量胆固醇和鞘磷脂。另一方面，它们的许多蛋白质具有催化活性并参与免疫反应。在之前的研究中，我们已经表明前列腺小体可能在略酸性pH值下与精子融合，从而改变精子质膜的组成。在本文中，我们研究了前列腺小体脂质的脂肪酸模式，发现它与精子膜脂质的脂肪酸模式完全不同。精子膜中常见的多不饱和磷脂酰胆碱在前列腺小体中很少见。因此，前列腺小体与精子之间的融合应通过在精子质膜中富集胆固醇、鞘磷脂和饱和甘油磷脂来稳定精子质膜。这将防止顶体反应过早发生。
