Bacteriophage T7-induced Endonuclease II

Abstract

A T74nduced endonuclease has been This enzyme has properties markedly previously described T7 endonuclease I. II exhibits optimal activity at pH 6.5 in the purified 400-fold.different from a T7 endonuclease presence of Mgff and sulfhydryl reagent.The enzyme has no activity towards single stranded DNA.Native DNA is degraded exclusively by the introduction of single strand breaks.Cleavage of the phosphodiester bond produces 5'-phosphoryl and 3'-hydroxyl termini.The 5'-end groups resulting from the action of the enzyme on T7 DNA contain all four deoxynucleoside monophosphates in approximately equal amounts.The limit product from digestion of native T7 DNA contains 13 breaks per molecule.