A 3'-deoxymononucleotide-producing nuclease from the marine sponge Verongia aerophoba. II. General properties.

The properties of a 3'-deoxymono-nucleotide-producing nuclease highly purified from the marine sponge Verongia aerophoba are described. The hydrolysis of heat-dentured DNA-proceeds at about five fold the rate of native, double-stranded DNA. The enzyme behaves as an exonuclease by producing 3'-deoxymononucleotides. Kinetic analysis by means of initial hyperchromicity at 260 nm indicates that the enzyme requries 120 mmol/l of mono-valent and 30 mmol/l of divalent cations with a clear dependence on ionic radius. The enzyme has a pH optimum at 4.7, the pH value of the isoelectric point is 6.1. The molecular weight has been evaluated at 62,000.