Xenopus laevis pancreatic DNase I: Purification and immunological characterization

Deoxyribonuclease I (DNase I) was purified from Xenopus laevis pancreas to apparent electrophoretic homogeneity using a series of column chromatograph ies. The purified enzyme showed a molecular mass of about 36 kDa and maximu m activity at pH 7.0-8.0, required divalent cations, Ca2+ and Mg2+, for its activity, and was inhibited by EDTA, EGTA and an antibody specific to the enzyme, but not by G-actin. The N-terminal amino acid sequence of the enzym e up to the 37th residue shared 38-44% homology with that of mammalian DNas es I derived from bovine, ovine, porcine, rat, mouse, rabbit and human. A s ystematic survey of DNase I activity distribution in 20 different kinds of frog tissues showed that the pancreas and rectum produced higher amounts th an other tissues. This is the first report concerning the purification and chemical and immunological characterization of frog pancreatic DNase I.