Native Bovine Deoxyribonuclease I

DNase I is an endonuclease that acts on phosphodiester bonds adjacent to pyrimidines to produce polynucleotides with terminal 5′-phosphates. In the presence of Mg2+, DNAse I cleaves each strand of DNA independently and the cleavage sites are random. Both DNA strands are cleaved at approximately the same site in the presence of Mn2+.2 The pH optimum is found to be between 7 and 8. Divalent cations such as Mn2+, Ca2+, Co2+, and Zn2+ are activators of the enzyme.3 A concentration of 5 mM Ca2+ stabilizes the enzyme against proteolytic digestion. DNAse I from bovine pancreas consists of four chromatographically distinguishable components, A, B, C, and D, with molar ratios being 4:1:1 respectively. Only minor amounts of D are found.4 2-Mercaptoethanol, chelators, sodium dodecyl sulfate (SDS) 5 and actin6 are known to inhibit the enzyme activity.