Purity ~90% (SDS-PAGE). Single-stranded DNA (ssDNA) bidirectional exonuclease involved in DNA repair. Probably involved in DNA repair following ultraviolet (UV) irradiation and interstrand cross-links (ICLs) damage. Has both 5'-3' and 3'-5' exonuclease activities with a strong preference for 5'-ends. Acts as a sliding exonuclease that loads at ssDNA ends and then slides along the ssDNA prior to cutting; however the sliding and the 3'-5' exonuclease activities are abolished upon binding to the replication protein A (RPA) complex that enforces 5'-directionality activity. Source: Recombinant protein corresponding to aa1-373 from human EXO5, fused to His-SUMO-Tag at N-terminal, expressed in E. coli. Molecular Weight: ~57.8kD AA