EN
A higher content of Tn and sialyl-Tn receptors in glycophorin A of blood group N than in that of blood group M was suggested by reactions with anti-Tn lectins. Analysis of [^-elimination products of two blood group M and two blood group N preparations by gas liquid chromatography-mass spectrometry showed that GalNAc- -ol was detectable in minor amounts in all analyzed samples and its content was higher in the products obtained from desialylated antigens. Moreover, the content of Gal N Ac- -ol detected in blood group N samples was almost twice as high as in respective blood group M samples. Since blood group M and N antigens differ in two amino-acid residues, our results support the existence of sequence-dependent differences in efficiency of substitution of glycophorin GalNAc-Ser/Thr residues with galactose.