Purification and characterization of a soluble form of lysosome-associated membrane glycoprotein-2 (lamp-2) from rat liver lysosomal contents.
Lysosomal membrane of rat liver contains a highly glycosylated protein referred to as lamp-2. Lamp-2 occurs to a significant extent in a soluble fraction of rat liver lysosomes. The soluble form of lamp-2 (SF-lamp-2) was purified to electrophoretic homogeneity. An apparent molecular weight M(r) of SF-lamp-2 on sodium dodecy sulfate-polyacrylamide gel electrophoresis was determined to be 91,000 which is 5,000 less than that of the membranous form of lamp-2 (MF-lamp-2). SF- and MF-lamp-2 were very similar to each other in terms of sialic acid content, NH2-terminal amino acid sequence and isoelectric point. Gel filtration data indicated that native SF-lamp-2 has an M(r) = 360,000. Taken together, SF-lamp-2 forms a tetrameric structure consisting of a homogenous polypeptide lacking a membrane-spanning domain and a cytoplasmic tail near the COOH-terminus.
Akasaki
K
K
Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Hiroshima, Japan.
Tsuji
H
H
D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000737:chemistry* / Q000302:isolation & purification*; D004591:Electrophoresis, Polyacrylamide Gel; D007526:Isoelectric Point; D008099:Liver / Q000737:chemistry* / Q000648:ultrastructure; D051907:Lysosomal Membrane Proteins; D008247:Lysosomes / Q000737:chemistry*; D008297:Male; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000302:isolation & purification*; D008970:Molecular Weight; D051381:Rats; D017208:Rats, Wistar; D012995:Solubility
D015703:Antigens, CD; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins