米曲霉β-N-乙酰己糖胺酶催化对硝基苯基β-D-N-乙酰半乳糖胺上的糖基转移至二糖受体以合成三糖。
Trisaccharide synthesis by glycosyl transfer from p-nitrophenyl beta-D-N-acetylgalactosaminide on to disaccharide acceptors catalysed by the beta-N-acetylhexosaminidase from Aspergillus oryzae.
作者信息
Singh S, Scigelova M, Critchley P, Crout D H
机构信息
Department of Chemistry, University of Warwick, Coventry, UK.
出版信息
Carbohydr Res. 1997 Dec;305(3-4):363-70. doi: 10.1016/s0008-6215(97)10030-1.
The beta-N-acetylhexosaminidase from Aspergillus oryzae catalysed the transfer of beta-D-N-acetylgalactosaminyl residues from p-nitrophenyl beta-D-N-acetylglucosaminide on to disaccharide acceptors consisting of thioethyl glycosides of alpha-D-Glc-(1-->4)-beta-D-Glc, beta-D-Glc-(1-->4)-beta-D-Glc and beta-D-Glc-(1-->6)-beta-D-Glc. The principle of 'anomeric control' was exemplified by the results which showed that an alpha-linkage between the units of the acceptor favoured exclusively the formation of a new (1-->4)-linkage, whereas the beta-configuration in the acceptor led to a mixture of (1-->4)- and (1-->3)-linked products, as observed for simple glycosides of monosaccharide acceptors. With the thioethyl beta-lactoside as acceptor, beta-D-Gal-(1-->6)-beta-D-Gal-(1-->4)-beta-D-GlcSEt was formed, owing to the action of residual beta-D-galactosidase activity in the N-acetylhexosaminidase on the thioethyl beta-lactoside acting as both donor and acceptor.
米曲霉的β-N-乙酰己糖胺酶催化对硝基苯基β-D-乙酰氨基葡萄糖苷中的β-D-N-乙酰半乳糖胺基残基转移至由α-D-葡萄糖-(1→4)-β-D-葡萄糖、β-D-葡萄糖-(1→4)-β-D-葡萄糖和β-D-葡萄糖-(1→6)-β-D-葡萄糖的硫代乙基糖苷组成的二糖受体上。“异头碳控制”原理通过以下结果得到例证：结果表明受体单元之间的α-连接仅有利于形成新的(1→4)-连接，而受体中的β-构型导致(1→4)-和(1→3)-连接产物的混合物，这与单糖受体的简单糖苷情况相同。以硫代乙基β-乳糖苷作为受体时，由于N-乙酰己糖胺酶中残留的β-D-半乳糖苷酶活性对同时作为供体和受体的硫代乙基β-乳糖苷起作用，形成了β-D-半乳糖-(1→6)-β-D-半乳糖-(1→4)-β-D-葡萄糖硫代乙酯。
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