Use of Synthetic H Disaccharides as Acceptors for Detecting Activities of UDP-GalNAc:Fuc α1-->2Galβ-R α1-->3-N-Acetylgalactosaminyltransferase in Plasma Samples from Blood Group A Subgroups

Concentrations of blood group A-specified alpha(1-->3)-N-acetylgalactosaminyltransferase (A enzyme) were measured in human plasma of blood groups A1, A2, and A3 by using chemically synthesized H disaccharides and H type 1 and type 2 trisaccharides attached to hydrophobic aglycones as acceptors. When the trisaccharides were used as acceptors, enzyme activities were reduced in samples from A2 and A3. However, the H disaccharides were shown to be good acceptors even for enzymes from A2 and A3, and no significant difference in enzyme concentration was detected in any of the plasma tested.