Relationship between two types of mouse sperm surface sites that mediate binding of sperm to the zona pellucida.
Relationship between two types of mouse sperm surface sites that mediate binding of sperm to the zona pellucida.
复制标题
介导精子与透明带结合的两种小鼠精子表面位点之间的关系。
DOI：
10.1095/biolreprod39.2.235
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发表时间：
1988
影响因子：
3.6
通讯作者：
B. Storey
中科院分区：
文献类型：
--
作者：
D. Benau;B. Storey
小鼠卵细胞透明带在小鼠精子表面至少有两个结合位点：一个具有可被尿嘧啶-5′-二磷酸二醛（UDPd）和α -乳清蛋白抑制的半乳糖基转移酶（GT）活性的位点，以及一个水解胍苯甲酸酯（GB）酯的胰蛋白酶抑制剂敏感（TI）位点。GT活性表征表明，以n -乙酰氨基葡萄糖为半乳糖受体，UDP半乳糖的Km为37 μ m， Vmax为0.37 pmol/min/10(6)个精子。12.5-100 microM的UDP半乳糖抑制精子与带完整卵子的结合，其浓度依赖性与GT活性密切相关（r = 0.95）。为了评估两种类型站点的独立性和空间关系，进行了交叉摄动研究。对硝基苯基- gb是TI位点特异性的低分子质量抑制剂，对GT位点的酶活性没有影响。相反，GT的特异性抑制剂UDPd对GB的水解没有影响。在GT实验中加入大豆胰蛋白酶抑制剂（SBTI）和在α -乳清蛋白或α - 1-酸性糖蛋白存在下进行GB水解实验时，发现弱抑制作用。酸溶带蛋白（ASZP）对GT反应的抑制作用较弱，而凝乳胰蛋白酶溶带蛋白（CSZP）对GT反应的抑制作用较强。ASZP抑制精子与带的结合，与抑制GB水解具有相同的浓度依赖性，但抑制GT酶活性的顺序与SBTI相同，表明在酶分析条件下，ASZP仅与TI位点结合。结果支持了这两种位点在结合其特定的带配体时是独立的假设，但足够接近，一个位点的酶活性被结合到另一个位点的大分子所扰动。在酶分析条件下，溶化带制剂与GT位点的不同相互作用表明，有利于该位点酶活性的条件可能会干扰该位点的生理结合功能。
There are at least two binding sites for the mouse egg zona pellucida on the surface of mouse sperm: a site with galactosyltransferase (GT) activity inhibitable by uridine-5'-diphosphate-dialdehyde (UDPd) and alpha-lactalbumin, and a trypsin inhibitor-sensitive (TI) site that hydrolyzes guanidinobenzoate (GB) esters. Characterization of GT activity gave the Km for UDP galactose as 37 microM with N-acetylglucosamine as galactose acceptor, and Vmax as 0.37 pmol/min/10(6) sperm. UDP galactose from 12.5-100 microM inhibited sperm binding to zona-intact eggs in a concentration-dependent manner with close correlation to GT activity (r = 0.95). To assess the independence and spatial relationship of the two types of site, cross-perturbation studies were performed. p-Nitrophenyl-GB, a low molecular mass inhibitor specific for the TI site, had no effect on the enzyme activity of the GT site. Conversely, UDPd, a specific inhibitor of GT, had no effect on GB hydrolysis. Weak inhibitions were found when soybean trypsin inhibitor (SBTI) was included with the GT assay and when GB hydrolysis was assayed in the presence of alpha-lactalbumin or asialo-agalacto-(alpha 1-acid glycoprotein). Acid-solubilized zona protein (ASZP) weakly inhibited the GT reaction, while stronger inhibition was seen with chymotrypsin-solubilized zona protein (CSZP). ASZP inhibited sperm binding to zonae with the same concentration dependence associated with inhibition of GB hydrolysis, but the inhibition of GT enzyme activity was on the same order as that found with SBTI, indicating that ASZP was only binding to the TI site under enzyme assay conditions. The results support the hypothesis that the two types of site are independent in binding their specific zona ligands, but are close enough for steric perturbation of the enzyme activity of one site by macromolecules bound to the other. The different interactions of solubilized zona preparations with the GT site under enzyme assay conditions are an indication that conditions which favor the enzyme activity of the site may interfere with the physiological binding functions of the site.