Micrococcal NucleaseMicrococcal nuclease catalyzes cleavage of both DNA and RNA to yield 3'-nucleotides. It exhibits exo- and endo-5'-phosphodiesterase activities. The enzyme catalyzes preferential endohydrolysis of the RNA and DNA at sites rich in adenylate or uridylate and deoxyadenylate or thymidylate. The enzyme has a molecular weight of 16,807 daltons and is calcium dependent. The pH optimum is 9.2 but varies depending upon the concentration of ionized calcium present.Chromatographically purified to be essentially homogeneous chromatographically and electrophoretically (SDS-PAGE). A lyophilized powder.