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Biochemical characterization of the monoclonal antibody‐defined ovarian carcinoma‐associated antigen SGA
Author(s) -
de Kretser Theonne A.,
Thorne Heather J.,
Picone Diana,
Jose David G.
Publication year - 1986
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910370511
Subject(s) - glycoprotein , monoclonal antibody , antigen , antibody , blot , cytoplasm , microbiology and biotechnology , cell , intracellular , biochemistry , glycosylation , biology , cell culture , chemistry , immunology , genetics , gene
The molecular nature of SGA, the ovarian‐carcinoma‐associated antigen defined by the MAb OM‐1, has been determined. The cell‐surface form of the SGA molecule is a glycoprotein with p1 <4.2, which on PAGE analysis has an apparent MW of approximately 360 kDa. This was the only OM‐1‐reactive species found on the cell surface. The apparent MW was unaffected by reducing conditions. The predominant cytoplasmic form of SGA is a non‐glycosylated 170‐kOa molecule with p1 6.5. Pulse‐chase experiments were complicated by the extremely slow rate of SGA synthesis. However, the data indicate that the SGA molecule is synthesized as a 190‐kDa protein, cleaved to yield a 170‐kDa non‐glycosylated intracellular form which is slowly glycosylated to the 360‐kDa cell‐surface species. Western blotting experiments revealed the presence of the 360‐kDa glycosylated molecule in human ovarian cell culture supernatants.