title: An anti-A-like lectin of Rana catesbiana eggs showing unusual reactivity.
abstract: A lectin was isolated from Rana catesbiana eggs that agglutinated blood group A-erythrocytes but did not agglutinate blood group B- or 0-erythrocytes. The lectin was purified by Sephadex G-75 gel filtration and by acrylamide gel electrophoresis at pH 4.3 and was proved to be homogeneous on electrophoresis, and the molecular weight was determined as 210 000. The specificity of A-like activity seems to direct towards three monosaccharide units: GalNAcalpha1 leads to 3(or 4)-Galbeta1 leads to 4(or 3)GlcNAcbeta1 leads to R based on inhibition of A-like hemagglutination by various monosaccharides, oligosaccharides and glycolipids, and based on precipitin reaction with various glycolipids and glycoproteins with known structures. Uniquely, A-like agglutination was inhibited not only by alpha-N-acetylgalactosamine analogs but also by N-acetyllactosamine analogs. The lectin showed therefore, two correlated specificities: one directed towards alpha-N-acetylgalactosamine residue at the terminal, and the other towards the subterminal Galbeta1 leads to 4betaGlcNAc (N-acetyllactosaminyl) residue. The reactivity due to the N-acetyllactosamine structure which is also found in erythrocyte ganglioside and in H-active chain might be blocked by sialyl or alpha-L-fucosyl substitution at the terminal, as the reactivity appeared after elimination of these sugar residues. In the A structure the reactivity due to N-acetyllactosaminyl residue seems not to be blocked by the presence of alpha-N-acetylgalactosamine at the terminal as A-agglutination was strongly inhibited by N-acetyllactosamine and its analogs. Although the lectin showed a single band on electrophoresis under different conditions, there is a possibility that the lectin may be a mixture of two proteins with different specificities as mentioned above.
mesh_terms: D000017:ABO Blood-Group System; D000116:Acetylgalactosamine / Q000494:pharmacology; D000371:Agglutination; D000818:Animals; D000918:Antibody Specificity; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D006017:Glycolipids / Q000494:pharmacology; D006023:Glycoproteins / Q000494:pharmacology; D006596:Hexosaminidases / Q000494:pharmacology; D006801:Humans; D037102:Lectins / Q000378:metabolism*; D008970:Molecular Weight; D009005:Monosaccharides / Q000494:pharmacology; D009439:Neuraminidase / Q000494:pharmacology; D009844:Oligosaccharides / Q000494:pharmacology; D010063:Ovum / Q000276:immunology*; D011892:Rana catesbeiana; D014357:Trypsin / Q000494:pharmacology; D005644:alpha-L-Fucosidase / Q000494:pharmacology
chemical_list: D000017:ABO Blood-Group System; D006017:Glycolipids; D006023:Glycoproteins; D037102:Lectins; D009005:Monosaccharides; D009844:Oligosaccharides; D006596:Hexosaminidases; D009439:Neuraminidase; D005644:alpha-L-Fucosidase; D014357:Trypsin; D000116:Acetylgalactosamine