Den1, den2 and den3, ATP-inhibited deoxyribonucleases from Dropsophila embryonic nuclei.

Three Drosophila embryonic deoxyribonucleases, designated den1, den2 and den3, are identified in nuclear extracts separated by glycerol density gradient centrifugation. Den1, removes short products from the 5'-ends of single-stranded DNA or double-stranded DNA with either blunt or 5'-recessed termini. Den2 is inactive with single-stranded DNA and acts as 3'-exonuclease with double-stranded DNA possessing either blunt or 3'-recessed termini. Den3 preferentially uses partial duplex DNA containing single-stranded gap and it catalyzes hydrolysis, in 3'-5' direction, of one of the shorter strands that flank the gap. Nucleolytic activities of den1, den2 and den3 are inhibited with ATP.