Srivastava G, Hindsgaul O, Palcic M M
Department of Chemistry, University of Alberta, Edmonton, Canada.
Carbohydr Res. 1993 Jul 5;245(1):137-44. doi: 10.1016/0008-6215(93)80066-n.
Bovine beta-(1-->4)-galactosyltransferase (GalT) transfers galactose from UDP-galactose to beta-D-GlcpNAc-terminating oligosaccharides to produce N-acetyllactosamine sequences. We report here the chemical synthesis, structural characterization and enzymatic evaluation of the very labile UDP-2-deoxy-D-lyxo-hexose ("UDP-2-deoxy-galactose," 2) as an alternate donor for GalT. Donor 2 had kinetic parameters, including a Km value of 51 microM, almost identical to those for the natural substrate UDP-galactose when beta-D-GlcpNAc-O(CH2)8COOMe was used as the acceptor. The product of the enzymatic transfer was isolated and confirmed to have the expected 2'-deoxy-N-acetyllactosamine sequence.
牛β-（1→4）-半乳糖基转移酶（GalT）将UDP-半乳糖中的半乳糖转移至以β-D- GlcpNAc结尾的寡糖上，生成N-乙酰乳糖胺序列。我们在此报告了极不稳定的UDP-2-脱氧-D- lyxo -己糖（“UDP-2-脱氧半乳糖”，2）作为GalT替代供体的化学合成、结构表征及酶活性评估。当使用β-D- GlcpNAc-O(CH2)8COOMe作为受体时，供体2的动力学参数，包括Km值为51μM，与天然底物UDP-半乳糖的几乎相同。分离出酶促转移产物并确认其具有预期的2'-脱氧-N-乙酰乳糖胺序列。
