Isolation and characterization of galactose-binding proteins from new-born mice.
Two galactose-binding proteins were purified from the soluble extracts of new-born mice by affinity chromatography using a column of lactamyl-Sepharose. The molecular masses of their subunits were 15 (galactose-binding protein 15K) and 16 (galactose-binding protein 16K) kDa, and the isoelectric points were 5.3 and 6.8, respectively. These galactose-binding proteins agglutinated formaldehyde-fixed trypsinized rabbit erythrocytes. Hemagglutinating activity was inhibited by galactose-containing saccharides and glycopeptides. N-Acetyllactosamine and asialo-glycopeptides having N-acetyllactosamine at non-reducing termini were found to be the most effective inhibitors so far examined. These results suggest that galactose-binding proteins can recognize lactosaminoglycans on erythrocyte surfaces. The elution patterns of gel filtration by high performance liquid chromatography showed galactose-binding protein 15K to form dimers of identical subunits, galactose-binding protein 16K to be monomeric, and neither to interact with each other under the conditions employed. The results obtained by immuno-blotting with antisera raised against purified galactose-binding proteins and amino acid analyses indicate that galactose-binding proteins 15K and 16K are not identical molecules. The distribution of galactose-binding protein 15K on frozen sections of new-born mice was surveyed by indirect immunofluorescence staining. Galactose-binding protein 15K was found widely distributed on many tissues, and distinct staining was observed in the liver and epidermis but not in the brain of unfixed samples.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000831:Animals, Newborn; D002135:Calcium-Binding Proteins; D050260:Carbohydrate Metabolism; D002352:Carrier Proteins / Q000302:isolation & purification*; D055598:Chemical Phenomena; D002621:Chemistry; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D006386:Hemagglutination Tests; D051379:Mice; D008813:Mice, Inbred ICR; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins
D000596:Amino Acids; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; C023550:galactose-binding protein