Peptide sequence: TCKSNWRGGW DWSQGKNRCP KGAQCLPFSH YFPTPADLCE KTWSNSFKAS Sequence homology: Guinea Pig: 85%; Horse: 90%; Human: 100%. FR4 is a heavily glycosylated 35 kD receptor for folic acid and the physiologic circulating form of the vitamin, N5-meth