title: Isolation and characterization of a glycopeptide from human senescent erythrocytes.
abstract: A glycopeptide (called "senescence-factor glycopeptide", SF-G) has been isolated from a tryptic digest of human erythrocytes by specific adsorption and elution from immobilized peanut lectin. SF-G was detectable in old but not in young erythrocytes isolated from the same unit of blood. It is present in small quantities, less than 1% of the D-galactose oxidase-borotritide-labeled D-galactosyl residues of erythrocytes. SF-G is free of sialic acid but is quite distinct from a similar glycopeptide isolated from completely desialylated erythrocytes. SF-G binds to spleen monocytes, and this property is abolished upon treatment of SF-G with beta-galactosidase. Some, but not all, of the oligosaccharide chains of the SF-G are of the O-glycosyl type, being released by an endo-N-acetyl-alpha-D-galactosaminidase.
mesh_terms: D002241:Carbohydrates / Q000032:analysis; D002846:Chromatography, Affinity; D004905:Erythrocyte Aging; D004912:Erythrocytes / Q000032:analysis*; D006020:Glycopeptides / Q000097:blood*; D006801:Humans; D010446:Peptide Fragments / Q000032:analysis; D014357:Trypsin
chemical_list: D002241:Carbohydrates; D006020:Glycopeptides; D010446:Peptide Fragments; D014357:Trypsin