Folate binding protein from kidney brush border membranes contains components characteristic of a glycoinositol phospholipid anchor

A study was conducted to prove that folate binding protein (FBP) from kidney brush border membranes contains a glycoinositol phospholipid anchor (GPL). Brush border membranes were isolated and labeled via (3H) folate. Results revealed the presence of individual residues common in GPL anchors which were covalently associated with FBP. Further tests also clarified the link between GPL-anchored FBP in biologocal membranes and soluble FBP in biological fluids.