CIRCULATORY HALF-LIFE BUT NOT INTERACTION WITH THE LUTROPIN CHORIONIC-GONADOTROPIN RECEPTOR IS MODULATED BY SULFATION OF BOVINE LUTROPIN OLIGOSACCHARIDES
CIRCULATORY HALF-LIFE BUT NOT INTERACTION WITH THE LUTROPIN CHORIONIC-GONADOTROPIN RECEPTOR IS MODULATED BY SULFATION OF BOVINE LUTROPIN OLIGOSACCHARIDES
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DOI：
10.1073/pnas.89.1.334
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发表时间：
1992-01-01
影响因子：
11.1
通讯作者：
BERANEK, MC
中科院分区：
文献类型：
--
作者：
BAENZIGER, JU;KUMAR, S;BERANEK, MC
某些糖蛋白激素，包括牛lutropin (bLH)，含有以so4 - 4galnac - β -1- 4glcnac - β -1- 2man - α序列结尾的天冬酰胺连接寡糖。为了确定这些含硫酸盐低聚糖的生物学意义，我们比较了天然bLH、脱硫bLH、重组bLH的性质，重组bLH是由中国地鼠卵巢细胞生产的，含有以唾液酸α -2- 3gal - β -1- 4glcnac - β -1- 2man - α为末端的天冬酰胺连接低聚糖，而不是硫酸低聚糖（bLH/CHO），以及脱氮bLH/CHO。使用培养的MA-10细胞（一种表达lutropin/绒毛膜促性腺激素受体的间质细胞肿瘤细胞系），我们发现天然bLH和去硫bLH在结合、cAMP产生或孕酮产生方面没有差异。因此，在lutropin/绒毛膜促性腺激素受体水平上，bLH寡糖的硫酸化不会调节bLH的生物活性。从bLH低聚糖中去除硫酸盐和从bLH/CHO低聚糖中去除唾液酸导致肝细胞唾液素糖蛋白受体从循环中快速清除。因此硫酸盐，像唾液酸一样，阻止唾液醛酸糖蛋白受体从循环中清除。与天然bLH相比，从循环中快速去除脱硫bLH导致刺激排卵所需的bLH量增加4至16倍。特别引人注目的是天然bLH和bLH/CHO的代谢清除率差异，分别为7.3% / min和1.7% / min。这些差异是出乎意料的，因为bLH和bLH/CHO在电荷或大小上没有显著差异。对bLH和bLH/CHO的不同代谢清除率表明，bLH上存在硫酸化而不是唾液化的低聚糖，导致循环半衰期更短，这对体内生物活性有显著影响。
Certain of the glycoprotein hormones, including bovine lutropin (bLH), bear asparagine-linked oligosaccharides terminating with the sequence SO4-4GalNAc-beta-1-4GlcNAc-beta-1-2Man-alpha. To establish the biologic significance of these sulfate-bearing oligosaccharides we have compared properties of native bLH, desulfated bLH, recombinant bLH produced in Chinese hamster ovary cells that bears asparagine-linked oligosaccharides terminating with sialic acid alpha-2-3Gal-beta-1-4GlcNAc-beta-1-2Man-alpha rather than sulfated oligosaccharides (bLH/CHO), and desialyzed bLH/CHO. Using cultured MA-10 cells, a Leydig cell tumor line expressing the lutropin/chorionic gonadotropin receptor, we have found no differences in binding, cAMP production, or progesterone production between native and desulfated bLH. Sulfation of bLH oligosaccharides does not, therefore, modulate bLH bioactivity at the level of the lutropin/chorionic gonadotropin receptor. Removal of sulfate from bLH oligosaccharides and sialic acid from bLH/CHO oligosaccharides results in rapid clearance from the circulation by the hepatocyte asialoglycoprotein receptor. Thus sulfate, like sialic acid, prevents clearance from the circulation by the asialoglycoprotein receptor. The rapid removal of desulfated bLH from the circulation causes a 4- to 16-fold increase in the amount of bLH required to stimulate ovulation compared with native bLH. Particularly striking were differences in the metabolic clearance rates for native bLH and bLH/CHO, 7.3% per min and 1.7% per min, respectively. These differences were unexpected because bLH and bLH/CHO do not differ significantly in charge or size. The different metabolic clearance rates obtained for bLH and bLH/CHO indicate that the presence of sulfated rather than sialylated oligosaccharides on bLH results in a shorter circulatory half-life, which has a significant impact on in vivo bioactivity.