A high-affinity folate binding protein in normal human leukocytes: ligand binding characteristics, ionic charge and molecular size.
High-affinity binding of [3H]folate to supernatant from homogenized human leukocytes containing large amounts of binding protein displayed apparent positive cooperativity. The DEAE-Sepharose CL-6B chromatographic profile of the supernatant at pH 6.3 contained a major peak of folate binding (Mr approx. 25 000) in the front effluent and a smaller more acidic peak (Mr approx. 25 000) that emerged after a rise in NaCl from 30 mmol/l to 1 mol/l. Triton X-100 solubilized cell sediment from the leukocyte homogenate contained some high-affinity folate binding activity (Mr approx 25 000), typically 5-10% of the total binding activity.
D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002846:Chromatography, Affinity; D058973:Folate Receptors, GPI-Anchored; D005492:Folic Acid / Q000097:blood*; D006801:Humans; D007700:Kinetics; D007962:Leukocytes / Q000378:metabolism*; D008970:Molecular Weight; D011956:Receptors, Cell Surface; D013347:Subcellular Fractions / Q000378:metabolism
D002352:Carrier Proteins; D058973:Folate Receptors, GPI-Anchored; D011956:Receptors, Cell Surface; D005492:Folic Acid