Xu W, Hamilton D W
Department of Cell Biology and Neuroanatomy, University of Minnesota Medical School, Minneapolis 55455, USA.
Mol Reprod Dev. 1996 Mar;43(3):347-57. doi: 10.1002/(SICI)1098-2795(199603)43:3<347::AID-MRD9>3.0.CO;2-Q.
Epididymis-secreted proteins D and E have been purified to homogeneity and partially characterized, and it is shown that monoclonal antibody (MAb) 4E9 (raised against a detergent extract of rat caudal epididymal sperm [Moore et al., 1994: Mol Reprod Dev 37(2):181-194]) recognizes protein E, but not protein D. The molecular weight of protein D (approximately 30 kD) is approximately 2 kD lower than protein E (approximately 32 kD). The NH2-terminus of each protein is blocked; however, microsequencing of internal peptides confirms earlier reports of significant sequence identity between the two proteins. High performance liquid chromatography tryptic peptide mapping showed peak differences between the two proteins, but it was not possible to obtain amino acid sequence in the peaks that were different. The epitope for MAb 4E9 was localized in the blocked NH2-terminus-CNBr peptide derived from protein E. The epitope was destroyed by protease treatment of protein E. Removal of N-linked oligosaccharides did not destroy the epitope for MAb 4E9 and did not affect the molecular weight difference between the proteins.
附睾分泌蛋白D和E已被纯化至同质并进行了部分特性分析，结果表明单克隆抗体（MAb）4E9（针对大鼠附睾尾部精子的去污剂提取物制备[Moore等人，1994：《分子生殖与发育》37(2):181 - 194]）识别蛋白E，但不识别蛋白D。蛋白D的分子量（约30 kD）比蛋白E（约32 kD）低约2 kD。每种蛋白的NH2末端均被封闭；然而，内部肽段的微量测序证实了早期关于这两种蛋白之间存在显著序列同一性的报道。高效液相色谱胰蛋白酶肽图谱显示这两种蛋白之间存在峰差异，但无法获得不同峰中的氨基酸序列。MAb 4E9的表位定位于源自蛋白E的封闭NH2末端 - CNBr肽段。该表位经蛋白酶处理蛋白E后被破坏。去除N - 连接寡糖不会破坏MAb 4E9的表位，也不影响这两种蛋白之间的分子量差异。
