title: Isolation and chemical and immunochemical characterization of the peanut-lectin-binding glycoprotein from human milk-fat-globule membranes.
abstract: Membrane glycoprotein with high Mr (HMr-MGP) was purified from neuraminidase-treated Triton X-100-solubilized human milk-fat-globule membranes by peanut-agglutinin (PNA) affinity chromatography. The high carbohydrate content (75%), blood-group-A activity and typical monosaccharide composition (L-fucose, D-galactose, N-acetyl-D-glucosamine and N-acetyl-D-galactosamine in the proportions 0.26:1.00:1.85:1.30) indicate that the isolated HMr-MGP is a mucinous substance. Fractionation of the oligosaccharides from alkaline-borohydride-treated HMr-MGP on Bio-Gel P-2 suggest that the PNA-binding sites are located mainly on longer (tetra- to deca-saccharide) alkali-labile bound oligosaccharide chains. Polyclonal antibodies raised against the HMr-MGP showed an antigenic distribution in histological sections that was comparable with the distribution of peroxidase-labelled-PNA-binding sites in both normal and malignant breast tissues. The positive immunohistological staining of some other tissue components with this antibody indicates that HMr-MGP is not strictly breast-associated. The functional role of HMr-MGP is unknown, but, since its expression is dependent on the differentiation state of secretory epithelial cells, it serves as a differentiation antigen that can be used for better functional characterization of breast cancers.
mesh_terms: D000230:Adenocarcinoma / Q000032:analysis; D001940:Breast / Q000032:analysis; D001943:Breast Neoplasms / Q000032:analysis; D002241:Carbohydrates / Q000032:analysis; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D000939:Epitopes / Q000032:analysis; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D037102:Lectins; D008565:Membrane Proteins / Q000302:isolation & purification; D008566:Membranes / Q000032:analysis; D008895:Milk, Human / Q000032:analysis*; D018396:Mucin-1; D019887:Peanut Agglutinin
chemical_list: D002241:Carbohydrates; D000939:Epitopes; D037102:Lectins; D008565:Membrane Proteins; D018396:Mucin-1; D019887:Peanut Agglutinin