Two types of α-galactosyltransferase with distinct isoelectric points were detected in serum from blood group B and group AB donors. One enzyme focusing at about pH 4.8 (4.4-5.6) had a reactively low enzymatic activity, whereas the other focusing at about pH 8.8 (7.2-9.8) had a higher enzymatic activity. On the other hand, all saliva samples from the same donors yielded a single peak with corresponding transferase activity, focusing at about pH 8.1 (6.9-9.0).