Stifani S, George R, Schneider W J
Department of Biochemistry, University of Alberta, Edmonton, Canada.
Biochem J. 1988 Mar 1;250(2):467-75. doi: 10.1042/bj2500467.
This paper describes the biochemical characterization of the chicken oocyte plasma-membrane receptor for one of the major lipid-carrying yolk proteins, vitellogenin (VTG). The receptor was extracted from oocyte membranes with the non-ionic detergent octyl-beta-D-glucoside and visualized by ligand blotting, with 125I-VTG as a protein with an apparent Mr of 96000, under non-reducing conditions. It exhibited high affinity for native chicken VTG (Kd 2 X 10(-7) M) but was unable to bind VTG with reductively methylated lysine residues or phosvitin (the phosphoserine-rich intracellular cleavage product of VTG). Polyclonal antibodies to the 96 kDa protein inhibited VTG binding to the receptor and were able to precipitate functional VTG-receptor activity from oocyte-membrane detergent extracts with a concomitant removal of the 96 kDa protein. Antibodies directed against the mammalian receptor for low-density lipoprotein showed cross-reactivity with the chicken oocyte VTG receptor, raising the possibility that lipoprotein receptors in birds are structurally related to those in mammalian species.
本文描述了鸡卵母细胞质膜上一种主要的携带脂质的卵黄蛋白——卵黄原蛋白（VTG）受体的生化特性。该受体用非离子去污剂辛基-β-D-葡萄糖苷从卵母细胞膜中提取出来，并在非还原条件下，以125I-VTG作为表观分子量为96000的蛋白质，通过配体印迹法进行可视化。它对天然鸡VTG具有高亲和力（解离常数Kd为2×10⁻⁷ M），但不能与具有还原甲基化赖氨酸残基的VTG或卵黄高磷蛋白（VTG富含磷酸丝氨酸的细胞内裂解产物）结合。针对96 kDa蛋白的多克隆抗体可抑制VTG与受体的结合，并能够从卵母细胞膜去污剂提取物中沉淀出功能性VTG受体活性，同时去除96 kDa蛋白。针对哺乳动物低密度脂蛋白受体的抗体与鸡卵母细胞VTG受体显示出交叉反应性，这增加了鸟类脂蛋白受体在结构上与哺乳动物物种的受体相关的可能性。
