OCCURRENCE OF A MUCIN-TYPE GLYCOPROTEIN IN NIDAMENTAL GLAND MUCOSUBSTANCE FROM THE SQUID ILLEX-ARGENTINUS
OCCURRENCE OF A MUCIN-TYPE GLYCOPROTEIN IN NIDAMENTAL GLAND MUCOSUBSTANCE FROM THE SQUID ILLEX-ARGENTINUS
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DOI：
10.2331/fishsci.60.193
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发表时间：
1994-04-01
影响因子：
1.9
通讯作者：
HANAOKA, Y
中科院分区：
文献类型：
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作者：
KIMURA, S;SUGIURA, Y;HANAOKA, Y
阿根廷滑柔鱼（Illex argentinus）的巢腺含有粘液物质，产卵后可形成类似卵团的粘液。在这项研究中，硫酸化糖蛋白制备的粘液物质溶解与温和的碱处理（0.4 N NaOH，4 ℃，4小时），然后用乙醇（50%）沉淀，其特征在于相对于其化学组成和大分子性质。糖蛋白约占粘液物质重量的35%，由22.6%蛋白质、73.0%碳水化合物和4.4%硫酸酯组成。大部分的糖蛋白被分离后，作为一个长的，不对称的，蛋白酶抗性片段，具有约1400 kDa的分子量的放线菌素酶消化。该片段的蛋白质骨架占18.7重量%，实际上由摩尔比为2：1：1的Thr、Pro和Ile组成。占总氨基酸45%的所有Thr残基被认为与主要由Gal、Fuc、GalNAc和未鉴定的氨基糖组成的寡糖的GalNAc残基连接。这些综合结果强烈表明，硫酸化糖蛋白是严重的O-糖基化，并定义为粘蛋白。然而，Thr-GalNAc键对β-消除（0.5 N NaOH，25 ℃，24 h）具有抗性。粘蛋白分子被认为是主要负责粘蛋白质的粘性和凝胶形成的性质的nidamental腺。
Nidamental glands of the squid Illex argentinus contain mucosubstance which forms jelly-like egg masses after spawning. In this study, a sulfated glycoprotein was prepared from the mucosubstance by solubilization with mild alkaline treatment (0.4 N NaOH, 4-degrees-C, 4 h), followed by precipitation with ethanol (50%), and was characterized with respect to its chemical composition and macromolecular properties. The glycoprotein accounted for about 35% of the mucosubstance by weight and comprised 22.6% protein, 73.0% carbohydrate, and 4.4% ester sulfate. A large part of the glycoprotein was isolated after actinase digestion as a long, asymmetric, protease-resistant fragment having a molecular mass of about 1400 kDa. The protein backbone of the fragment accounted for 18.7% by weight and was composed virtually of Thr, Pro, and Ile in the molar ratio of 2:1:1. All Thr residues, comprising 45% of the total amino acids, were considered to link to GalNAc residues of oligosaccharides consisting mainly of Gal, Fuc, GalNAc, and an unidentified amino sugar. These combined results strongly suggest that the sulfated glycoprotein is heavily O-glycosylated and defined as a mucin. The Thr-GalNAc linkages, however, were resistant to beta-elimination (0.5 N NaOH, 25-degrees-C, 24 h). The mucin molecules were assumed to be mainly responsible for the viscous and gel-forming properties of the nidamental gland mucosubstance.