Valladares L, Erices A, Lioi X, Iturriaga H
Laboratorio de Hormonas y Receptores, INTA, Universidad de Chile, Santiago, Chile.
Steroids. 2000 May;65(5):275-80. doi: 10.1016/s0039-128x(00)00086-6.
In previous reports we have demonstrated high plasma levels of sex hormone-binding globulin (SHBG) in asymptomatic alcoholic men. In the present work the physicochemical properties of SHBG from plasma of noncirrhotic alcoholic patients have been further compared with SHBG of control subjects. Steroid binding to SHBG was similar for the two groups: alcoholic men, K(d) of 0.62 +/- 0.07 nM and control individuals, K(d) of 0.70 +/- 0.10 nM. The structure of oligosaccharides attached to SHBG from controls and alcoholic men were determined by using serial chromatography. Our data indicated that 7% of SHBG of control individuals was not retarded by the Con-A column, whereas approximately 30% of SHBG of alcoholic men eluted in the void volume of Con A. Approximately 46% of SHBG of alcoholics applied to Con A, possessed biantennary complex oligosaccharides, as indicated by the fact that it could be eluted with methyl-alpha-D-glucopyranoside and by its retention on wheat germ agglutinin; in contrast, when SHBG from control men was analyzed, approximately 51% was eluted with methyl-alpha-D-glucopyranoside. Approximately 9% of the biantennary complex oligosaccharides on SHBG of control men and none of those on SHBG from alcoholic men were fucosylated on the chitobiose core, as determined by chromatography on Lenn culinaris lectin. Galactosylated oligosaccharides were also present on the SHBG fraction as indicated by its interaction with Ricinus communis-I. Approximately 24% of SHBG of alcoholic men and 39% of those on SHBG from control individuals applied to Con-A were retained and could be eluted with methyl-alpha-D-mannopyranoside. Evidence based on the binding on mannoside-eluted SHBG to Con-A, wheat germ agglutinin, and R. communis-I indicated that at least the SHBG in this fraction, from alcoholics or controls, contained two glycosylation sites and that the sites were differentially glycosylated.
在之前的报告中，我们已证明无症状酒精性男性的血浆中性激素结合球蛋白（SHBG）水平较高。在本研究中，我们进一步比较了非肝硬化酒精性患者血浆中SHBG与对照受试者SHBG的物理化学性质。两组中类固醇与SHBG的结合情况相似：酒精性男性的解离常数（K(d)）为0.62±0.07 nM，对照个体的K(d)为0.70±0.10 nM。通过连续色谱法测定了对照者和酒精性男性SHBG上连接的寡糖结构。我们的数据表明，7%的对照个体的SHBG不被伴刀豆球蛋白A（Con-A）柱阻滞，而约30%的酒精性男性的SHBG在Con A的空体积中洗脱。应用于Con A的酒精性患者的SHBG中约46%具有双天线复杂寡糖，这一事实表明它可以用甲基-α-D-吡喃葡萄糖苷洗脱，并保留在麦胚凝集素上；相比之下，分析对照男性的SHBG时，约51%用甲基-α-D-吡喃葡萄糖苷洗脱。通过扁豆凝集素色谱法测定，对照男性SHBG上约9%的双天线复杂寡糖且酒精性男性SHBG上的双天线复杂寡糖均未在壳二糖核心上岩藻糖基化。如与蓖麻凝集素-I的相互作用所示，半乳糖基化寡糖也存在于SHBG组分中。应用于Con-A的酒精性男性的SHBG中约24%以及对照个体的SHBG中39%被保留，并可用甲基-α-D-甘露吡喃糖苷洗脱。基于甘露糖苷洗脱的SHBG与Con-A、麦胚凝集素和蓖麻凝集素-I的结合证据表明，至少该组分中来自酒精性患者或对照者的SHBG含有两个糖基化位点，且这些位点的糖基化情况不同。
