Fpg is a key enzyme in the DNA base excision repair pathway (BER). It catalyses the excision of a broad spectrum of modified purines. Fpg has both DNA glycosylase activity that removes the mutated base and AP-lyase activity that releases ribose leaving both 5′- and 3′-phosphorylated ends in the DNA. The zinc finger motif at its C-terminus is responsible for the DNA binding and AP-lyase activity. In addition, its N-terminal proline acts as a nucleophile to produce a Schiff base intermediate that is essential for enzyme action.