Liberation of N-acetylglucosamine-6-sulfate by human beta-N-acetylhexosaminidase A.
Liberation of N-acetylglucosamine-6-sulfate by human beta-N-acetylhexosaminidase A.
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人 β-N-乙酰氨基己糖苷酶 A 释放 N-乙酰氨基葡萄糖-6-硫酸盐。
DOI：
10.1016/s0021-9258(18)42985-7
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
W. Gilberg
中科院分区：
文献类型：
--
作者：
H. Kresse;W. Fuchs;J. Glössl;D. Holtfrerich;W. Gilberg
对硝基苯基-6-磺基-2-乙酰氨基-2-脱氧-β-D-吡喃葡萄糖苷和在非还原端带有N-乙酰葡糖胺-6-硫酸盐残基的硫酸角质素衍生寡糖的降解的第一步被认为是通过特定硫酸酯酶的作用完成的（Kresse, H.、Paschke, E.、von Figura, K.、Gilberg, W.和Fuchs） W. (1980) 国家科学院。 77, 6822-6826)。然而，在从人胎盘中纯化时，该活性与 β-N-乙酰氨基己糖苷酶的同工酶 A 进行共色谱分析，并且具有与后一种酶相同的电泳迁移率。该活性是由针对 β-N-乙酰氨基己糖苷酶的特异性抗血清引发的。在 Tay-Sachs 和 Sandhoff 成纤维细胞中发现了明显的酶缺乏。纯化的酶从显色底物中释放对硝基苯酚以及含有等摩尔量的己糖胺和硫酸盐的第二产物。该产品具有与硫酸化N-乙酰氨基葡萄糖相同的电泳和色谱行为。它可以被高碘酸盐降解成更小的带电片段。将硫酸角质素衍生的寡糖与 β-N-乙酰氨基己糖苷酶 A 一起孵育，类似地导致 N-乙酰氨基葡萄糖-6-硫酸盐的释放。该酶对三硫酸化四糖表现出最高的亲和力，并且对硫酸化和非硫酸化对硝基苯基衍生物表现出相似的 Km。
The first step of the degradation of p-nitrophenyl-6-sulfo-2-acetamido-2-deoxy-beta-D-glucopyranoside and of keratan sulfate-derived oligosaccharides bearing N-acetylglucosamine-6-sulfate residues at the nonreducing end was considered to be accomplished by the action of a specific sulfatase (Kresse, H., Paschke, E., von Figura, K., Gilberg, W., and Fuchs W. (1980) Proc. Natl. Acad. Sci. U. S. A. 77, 6822-6826). In purification from human placenta, however, this activity co-chromatographed with isoenzyme A of beta-N-acetylhexosaminidase and had the same electrophoretic mobility as the latter enzyme. The activity was precipitated by a specific antiserum against beta-N-acetylhexosaminidase. A pronounced enzyme deficiency was found in Tay-Sachs and Sandhoff fibroblasts. The purified enzyme released p-nitrophenol from the chromogenic substrate as well as a second product which contained equimolar amounts of hexosamine and sulfate. This product had the same electrophoretic and chromatographic behavior as sulfated N-acetylglucosamine. It could be degraded by periodate to a smaller charged fragment. Incubation of keratan sulfate-derived oligosaccharides with beta-N-acetylhexosaminidase A analogously resulted in the liberation of N-acetylglucosamine-6-sulfate. The enzyme showed the highest affinity towards a trisulfated tetrasaccharide and exhibited a similar Km for the sulfated and the unsulfated p-nitrophenyl derivative.