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Isolation and biochemical characterization of the soluble and membrane forms of folate binding protein expressed in the ovarian carcinoma cell line IGROV1
Author(s) -
Tomassetti Antonella,
Coney Leslie R.,
Canevari Silvana,
Miotti Silvia,
Facheris Patrizia,
Zurawski Vincent R.,
Colnaghi Maria I.
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)81510-7
Subject(s) - biochemistry , cell culture , biology , binding protein , monoclonal antibody , ovarian carcinoma , ovarian carcinomas , membrane protein , cell , microbiology and biotechnology , membrane , antibody , ovarian cancer , cancer , immunology , gene , genetics
The human ovarian carcinoma cell line, IGROV1, produces two forms of folate binding protein (FBP), the membrane form that is anchored to the cell surface by a glycosylphosphatidylinositol tail and the soluble form that is shed into the tissue culture medium. Both forms are recognized by the monoclonal antibodies MOv18 and MOv19. Here we describe their purification and biochemical characterization. The purified soluble protein appeared as a single band with an apparent M r of 36 kDa after SDS‐PAGE, whereas the membrane form appeared as a single band with an apparent M r of 38 kDa. The size difference between the two forms of FBP was confirmed by gel filtration of both the native and the N ‐glycanase‐treated proteins. Both purified proteins had equal capacity to bind folic acid. The immunological cross‐reactivity and the folic acid binding capability of the FBPs extracted from IGROV1 gave more evidence of the possible existence of a precursor‐product relationship between them.