Charge heterogeneity of the folate binding protein in normal human leukocytes.
The DEAE-Sepharose CL-6B chromatographic profile of supernatant from homogenized normal human leukocytes containing large amounts of folate binder revealed two peaks of binding activity. A minor binder (I) eluted with the equilibrating buffer (1 mM sodium phosphate of pH 6.0), while the major binder (II) first eluted after the initiation of a linear phosphate gradient with 200 mM sodium phosphate of pH 7.6 as the limiting buffer. Binder II was thus a more acidic protein since it required elution by a salt-pH gradient. Binding of [3H] folate to binder II was of a high-affinity type (K = 10(10) M-1) and displayed positive cooperativity.
D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D058973:Folate Receptors, GPI-Anchored; D005492:Folic Acid / Q000097:blood*; D006801:Humans; D007700:Kinetics; D007962:Leukocytes / Q000378:metabolism*; D011956:Receptors, Cell Surface; D012016:Reference Values
D002352:Carrier Proteins; D058973:Folate Receptors, GPI-Anchored; D011956:Receptors, Cell Surface; D005492:Folic Acid