title: alpha-N-acetyl-D-galactosaminyl- and alpha-D-galactosyltransferase activities in sera of cis AB blood group individuals.
abstract: Thirteen cis AB persons from five families were examined for serum glycosyltransferase activities associated with the biosynthesis of A and B blood group characters. Their transferases were generally homogeneous within one family, except for A2/cis AB genotypes, whose A enzyme level was similar to the A2 normal sera, but they varied from one family to another. These activities differed quantitatively and qualitatively from A, B and AB normal sera. Studies of A transferase showed variations in the pH-dependent curve, the effect of cofactors and the capacity of conversion of O red cells into A-active cells. Moreover, A and B transferases behaved differently with respect to their relative levels than did AB heterozygous normal sera. The results were discussed and it was suggested that a mutation of a single enzyme transferring both galactose and N-acetyl-galactosamine could explain these properties.
mesh_terms: D000017:ABO Blood-Group System; D002874:Chromosome Mapping; D002877:Chromosomes, Human / Q000648:ultrastructure; D004912:Erythrocytes / Q000201:enzymology; D005260:Female; D005688:Galactosamine / Q000378:metabolism; D005700:Galactosyltransferases / Q000378:metabolism*; D005796:Genes; D005838:Genotype; D006801:Humans; D008297:Male
chemical_list: D000017:ABO Blood-Group System; D005688:Galactosamine; D005700:Galactosyltransferases