title: Purification, some properties, and tissue distribution of a major lysosome-associated membrane glycoprotein (r-lamp-2) of rat liver.
abstract: We previously purified and characterized a major lysosomal membrane glycoprotein (r-lamp-1) from rat liver [Akasaki et al. (1990) Chem. Pharm. Bull. 38, 2766-2770]. The present study describes the purification of another major lysosomal membrane glycoprotein (r-lamp-2) from rat liver and compares the tissue distribution of r-lamp-1 and r-lamp-2 in rats. R-lamp-2 was purified to apparent electrophoretic homogeneity from rat liver by a simple method with a protein yield of approximately 4.0 micrograms/g wet weight of liver. The purification procedure includes: preparation of tritosomal membranes, extraction of tritosomal membranes with Lubrol PX, wheat germ agglutinin (WGA)-Sepharose affinity chromatography, and monoclonal antibody-Sepharose affinity chromatography. R-lamp-2 exhibited an Mr of 96,000 on SDS-PAGE and had an acidic pI of less than 3.5. R-lamp-2 contained 52.3% carbohydrates. Its carbohydrate moieties were composed of numerous sialyl complex type N-linked oligosaccharides and small amounts of O-linked oligosaccharides. Both r-lamp-1 and r-lamp-2 were detected in all rat tissues examined by immunoblot analyses, while their apparent molecular weights differed among the tissues. Immunological quantitative analysis showed that the protein concentrations of r-lamp-2 were consistently lower than those of r-lamp-1 in all the tissues tested. There was a significant correlation with a regression coefficient of 0.86 in the tissue distribution between r-lamp-1 and r-lamp-2. A good correlation was also observed in the tissue distribution between acid phosphatase and r-lamp-2.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Hiroshima.
authors.forename: K
authors.initials: K
authors.lastname: Akasaki
authors.forename: Y
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: K
authors.initials: K
authors.lastname: Furuno
authors.forename: H
authors.initials: H
authors.lastname: Tsuji
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD; D002241:Carbohydrates / Q000032:analysis; D008099:Liver / Q000737:chemistry*; D051907:Lysosomal Membrane Proteins; D008247:Lysosomes / Q000737:chemistry*; D008297:Male; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution
chemical_list: D015703:Antigens, CD; D002241:Carbohydrates; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins