Suzuki T, Nakajima K, Yamamoto A, Suzuki K, Yamamoto K, Yamanaka H
Department of Urology, School of Medicine, Gunma University, Maebashi, Japan.
Tohoku J Exp Med. 1994 Sep;174(1):19-30. doi: 10.1620/tjem.174.19.
Binding studies of metallothionein and rat spermatozoa were performed using 125I-Tyr-metallothionein (125I-MT). Reactions between 125I-MT and spermatozoa indicated that MT bound in two forms, namely, middle affinity (Kd1 = 2 x 10(-9) M) binding and low affinity (Kd2 = 1 x 10(-8) M) binding. Labeled MT binding to spermatozoa was inhibited by adding anti-MT antibody. Total binding reactions of MT were temperature and incubation time dependent. By transmission electron microscopy using a gold conjugate (indirect method), gold particles bound to MT were shown to bind to the cell membrane of the head and the proximal portion of the tail. By optical autoradiography, grains of labeled MT were localized mainly in the head and the proximal portion of the tail. By electron microscopical autoradiography, grains of labeled MT were identified mainly in the cell membrane of the head and tail and partly in the nucleus. These results suggest that MT has both specific and non-specific binding sites on the spermatozoal membrane.
利用¹²⁵I-酪氨酸-金属硫蛋白（¹²⁵I-MT）对金属硫蛋白与大鼠精子进行结合研究。¹²⁵I-MT与精子之间的反应表明，MT以两种形式结合，即中等亲和力（Kd1 = 2×10⁻⁹ M）结合和低亲和力（Kd2 = 1×10⁻⁸ M）结合。添加抗MT抗体可抑制标记的MT与精子的结合。MT的总结合反应取决于温度和孵育时间。通过使用金偶联物的透射电子显微镜（间接法），显示与MT结合的金颗粒与头部细胞膜和尾部近端结合。通过光学放射自显影，标记MT的颗粒主要定位于头部和尾部近端。通过电子显微镜放射自显影，标记MT的颗粒主要在头部和尾部的细胞膜中被鉴定出来，部分在细胞核中。这些结果表明，MT在精子膜上既有特异性结合位点，也有非特异性结合位点。
