Recognition of synthetic O-methyl, epimeric, and amino analogues of the acceptor α-L-Fucp-(1 → 2)-β-D-Galp-OR glycosyltransferases
作者:Todd L. Lowary、Ole Hindsgaul
DOI:10.1016/0008-6215(94)84275-2
日期:1994.1
The disaccharide alpha-L-Fuc p-(1-->2)-beta-D-Gal p-O-(CH2)7CH3 (6) is an acceptor for the glycosyltransferases responsible for the biosynthesis of the A and B blood-group antigens. These enzymes respectively transfer GalNAc and Gal in an alpha linkage to OH-3 of the Gal residue in 6. All eight possible O-methyl, epimeric, and amino analogues of 6 having modifications on the target Gal residue were
二糖α-L-Fucp-(1→2)-β-D-GalpO-(CH2)7CH3(6)是负责A和B血型抗原生物合成的糖基转移酶的受体。这些酶分别将GalNAc和Gal转移到6中Gal残基的OH-3的alpha键上。化学合成了8种可能的在目标Gal残基上有修饰的O-甲基,差向异构体和氨基类似物,并进行了动力学评估作为A和B糖基转移酶的底物和抑制剂。该结果支持了较早的发现,即两种酶均能耐受Gal残基的3位和6位羟基取代。但是,取代或取代了Gal残基的OH-4可以消除识别。6-O-甲基和6-氨基化合物是两种酶的底物,而3-表异构体(10)和3-氨基(12)化合物是抑制剂。对于B转移酶,Ki是7.8 microM的竞争性抑制剂。由于抑制作用的模式复杂,尝试用B转移酶确定12 Ki的尝试失败。同样,10和12都是A转移酶的有效抑制剂,但是由于其抑制方式很复杂,类似于B转移酶,因此无法计算出抑制常数。使用A转移酶,估计12的Ki在200