Purity: > 90% by SDS - PAGE Format: Liquid. In 20 mM Tris-HCl buffer (pH8.0) containing 1mM DTT 10% glycerol . FEN-1, also known as Flap structure-specific endonuclease 1, removes 5' overhanging flaps in DNA repair and processes the 5' ends of Okazaki fragments in lagging strand DNA synthesis. The protein is a member of the XPG/RAD2 endonuclease family and is one of ten proteins essential for cell-free DNA replication. FEN-1 is highly homologous to yeast Rad2. The C-terminal region of FEN-1 may bind to PCNA, thus allowing FEN-1 to function as an exonuclease in DNA replication. Recombinant human FEN-1 protein was expressed in E.coli and purified by using conventional chromatography techniques.