title: Evidence for the lumenal location of the 53 kDa glycoprotein of sarcoplasmic reticulum.
abstract: The 53 kDa glycoprotein from sarcoplasmic reticulum was shown to be protected from proteolysis by trypsin, V8 proteinase and proteinase K in intact vesicles yet readily digested in the presence of the non-denaturing detergent C12E8. Competitive ELISAs with a library of seven monoclonal antibodies raised against the 53 kDa glycoprotein showed that the epitopes for these antibodies were only accessible in C12E8 solubilised and not intact sarcoplasmic reticulum. When the monoclonal antibodies against the 53 kDa glycoprotein were assessed for their effect on the uptake of Ca2+ by sarcoplasmic reticulum no effect was detected; neither were these antibodies able to augment the inhibitory influences of anti-(Ca(2+)-Mg2+)-ATPase monoclonal antibodies on Ca2+ uptake. These data indicate that the 53 kDa glycoprotein is located in the lumen of the sarcoplasmic reticulum.
authors.affiliation: SERC Centre for Molecular Recognition, University of Southampton, UK.
authors.forename: I
authors.initials: I
authors.lastname: Matthews
authors.forename: A M
authors.initials: AM
authors.lastname: Mata
authors.forename: A G
authors.initials: AG
authors.lastname: Lee
authors.forename: J M
authors.initials: JM
authors.lastname: East
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D002118:Calcium / Q000378:metabolism; D003902:Detergents; D019286:Endopeptidase K; D000939:Epitopes / Q000032:analysis; D005260:Female; D006023:Glycoproteins / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000737:chemistry* / Q000378:metabolism; D012697:Serine Endopeptidases; D014357:Trypsin
chemical_list: D000911:Antibodies, Monoclonal; D003902:Detergents; D000939:Epitopes; D006023:Glycoproteins; D012697:Serine Endopeptidases; D014357:Trypsin; D019286:Endopeptidase K; D002118:Calcium