Endo M, Namiki O, Yosizawa Z
Tohoku J Exp Med. 1980 Sep;132(1):37-41. doi: 10.1620/tjem.132.37.
To elucidate the mode of the exertion of glycosidase activities in the catabolism of the tissue glycosaminoglycans (GAG), the terminal monosaccharides of the carbohydrate chains of urinary GAG in the most prominent subfraction (40% Fr-1.25 M Fr) among the subfractions obtained in a previous paper (Endo et al. 1980a) were investigated. The results of determination of the reducing hexuronic acid and N-acetylhexosamine before and after digestion of the subfraction with beta-glucuronidase and beta-N-acetylhexosaminidase, together with previous data indicated that 0.36 and 0.37 mol of glucuronic acid and N-acetylgalactosamine, respectively, per mol of the subfraction were located at the non-reducing terminals of the carbohydrate chains. The remaining portion (0.27 mol per mol) of the non-reducing ends might be mostly occupied by the sulfated N-acetylgalactosamine residues. On the other hand, 0.25, 0.16 and 0.34 mol of glucuronic acid, N-acetylgalactosamine and xylose, respectively, per mol of the subfraction were indicated to the present at the reducing terminals of the carbohydrate chains. The remaining portion (0.25 mol per mol) of the reducing ends might be mostly occupied by the galactose residues and/or the N-acetylgalactosamine 4-sulfate residues. The present observations provided with evidence for the action of endo-beta-glucuronidase and endo-beta-N-acetylhexosaminidase on the tissue GAG, specifically on chondroitin sulfates.
为阐明糖苷酶在组织糖胺聚糖（GAG）分解代谢中发挥作用的方式，我们对先前论文（Endo等人，1980a）中获得的亚组分中最主要的亚组分（40% Fr - 1.25 M Fr）尿GAG碳水化合物链的末端单糖进行了研究。用β - 葡萄糖醛酸酶和β - N - 乙酰己糖胺酶消化该亚组分前后还原己糖醛酸和N - 乙酰己糖胺的测定结果，以及先前的数据表明，每摩尔该亚组分分别有0.36摩尔葡萄糖醛酸和0.37摩尔N - 乙酰半乳糖胺位于碳水化合物链的非还原末端。非还原端的其余部分（每摩尔0.27摩尔）可能大部分被硫酸化的N - 乙酰半乳糖胺残基占据。另一方面，每摩尔该亚组分分别有0.25摩尔葡萄糖醛酸、0.16摩尔N - 乙酰半乳糖胺和0.34摩尔木糖存在于碳水化合物链的还原末端。还原端的其余部分（每摩尔0.25摩尔）可能大部分被半乳糖残基和/或N - 乙酰半乳糖胺4 - 硫酸酯残基占据。目前的观察结果为内切β - 葡萄糖醛酸酶和内切β - N - 乙酰己糖胺酶对组织GAG，特别是对硫酸软骨素的作用提供了证据。
