Mammalian cells contain a second nucleocytoplasmic hexosaminidase.
Mammalian cells contain a second nucleocytoplasmic hexosaminidase.
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DOI：
10.1042/bj20081630
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发表时间：
2009-04-01
期刊：
影响因子：
--
通讯作者：
Wilson IB
中科院分区：
文献类型：
--
作者：
Gutternigg M;Rendić D;Voglauer R;Iskratsch T;Wilson IB
大约30年前，对哺乳动物组织的研究表明，哺乳动物细胞中存在两种胞质氨基己糖苷酶;其中一种最近以重组形式表征，并且由于其能够从各种核和细胞质蛋白质中切割β-N-乙酰葡糖胺残基，因此在细胞功能中具有重要作用。然而，第二种胞质氨基己糖苷酶（命名为氨基己糖苷酶D）的分子性质仍然不清楚。在本研究中，我们分子生物学首次人类和小鼠重组形式的酶，编码的HEXDC基因，这似乎对应于氨基己糖苷酶D的底物特异性，pH依赖性和温度稳定性;此外，myc标记的形式，这种新的氨基己糖苷酶显示核胞质定位。相应基因的转录物在许多鼠组织中表达。基于其序列，该酶与由HEXA和HEXB基因编码的溶酶体氨基己糖苷酶亚基一起沿着代表了从哺乳动物来源发现的第三类20糖苷酶。
Some thirty years ago, work on mammalian tissues suggested the presence of two cytosolic hexosaminidases in mammalian cells; one of these has been more recently characterised in recombinant form and has an important role in cellular function due to its ability to cleave β-N-acetylglucosamine residues from a variety of nuclear and cytoplasmic proteins. However, the molecular nature of the second cytosolic hexosaminidase, named hexosaminidase D, has remained obscure. In the present study, we molecularly characterise for the first time the human and murine recombinant forms of enzymes, encoded by HEXDC genes, which appear to correspond to hexosaminidase D in terms of substrate specificity, pH dependency and temperature stability; furthermore, a myc-tagged form of this novel hexosaminidase displays a nucleocytoplasmic localisation. Transcripts of the corresponding gene are expressed in a number of murine tissues. Based on its sequence, this enzyme represents, along with the lysosomal hexosaminidase subunits encoded by the HEXA and HEXB genes, the third class 20 glycosidase to be found from mammalian sources.