Diastereotopic substrates of β-d-galactosidase from Escherichia coli as probes for a catalytically active, protonating group
作者:Hans Fritz、Jochen Lehmann、Peter Schlesselmann
DOI:10.1016/0008-6215(83)88220-2
日期:1983.2
Abstract With 3,4,5,7-tetra- O -acetyl-2,6-anhydro- d - glycero - l - manno -heptononitrile as the starting material, the diastereotopic, enolic sugar derivatives ( Z )-3,7-anhydro-2-deoxy- d - galacto -oct-2-enononitrile ( 2 ) and ( Z )- ( 5 ) and ( E )-3,7-anhydro-1,2-di-deoxy- d - galacto -oct-2-enitol ( 8 ) were prepared by multistep syntheses, and structurally investigated by 1 H- and 13 C-n.m
摘要以3,4,5,7-四-O-乙酰基-2,6-脱水-d-甘油-甘露聚糖-庚腈为原料,非对映体烯醇糖衍生物(Z)-3,7-脱水-2-脱氧-d-半乳糖-辛基-2-烯腈(2)和(Z)-(5)和(E)-3,7-脱水-1,2-二脱氧-d-半乳糖-辛基通过多步合成制备-2-烯醇(8),并通过1 H-和13 Cn.mr光谱进行结构研究。化合物2和5易受β-d-半乳糖苷酶催化的烯醇式双键水合反应,而化合物5的异构体化合物8不能被酶合水合。因为腈2的水合产物中的质子确实在质子介质中交换,所以只有5个质子可以用作非对映体探针来阐明酶促质子化的立体化学。