title: Purification and partial characterization of rat liver folate binding protein: cytosol I.
abstract: The high molecular weight folate binding protein of rat liver cytosol has been purified to apparent homogeneity. Purification was achieved by using a combination of gel filtration, O-(diethylaminoethyl)cellulose chromatography, and affinity chromatography. This folate binding protein was initially identified during purification by an in vivo labeling procedure involving intraperitoneal injection of [3H]folic acid prior to sacrifice and subsequently by its ability to bind naturally reduced [3H]folate polyglutamates in vitro. A molecular weight of 210 000 was estimated by gel chromatography. This is distinct from the trifunctional formyl-methenyl-methylene synthetase of rat liver which has a molecular weight of 225 000. Sodium dodecyl sulfate electrophoresis revealed a single band with a molecular weight of about 100 000 which suggests the native protein is composed of two identical subunits. The partially purified protein contains bound tetrahydropteroylpentaglutamate.
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000302:isolation & purification* / Q000378:metabolism; D002846:Chromatography, Affinity; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003600:Cytosol / Q000032:analysis; D058973:Folate Receptors, GPI-Anchored; D005575:Formyltetrahydrofolates; D050938:Glycine N-Methyltransferase; D008099:Liver / Q000032:analysis*; D008970:Molecular Weight; D051381:Rats; D011956:Receptors, Cell Surface; D013763:Tetrahydrofolates / Q000378:metabolism; D011623:gamma-Glutamyl Hydrolase
chemical_list: D002352:Carrier Proteins; D058973:Folate Receptors, GPI-Anchored; D005575:Formyltetrahydrofolates; D011956:Receptors, Cell Surface; D013763:Tetrahydrofolates; D050938:Glycine N-Methyltransferase; C494512:Gnmt protein, rat; D011623:gamma-Glutamyl Hydrolase