Purification and Characterization of an Acid Deoxyribonuclease from the Cultured Mycelia of Cordyceps sinensis

Maoqing Ye, Zheng Hu, Ying Fan, Ling He, Fubao Xia, Guolin Zou
2004 BMB Reports  
A new acid deoxyribonuclease (DNase) was purified from the cultured mycelia of Cordyceps sinensis, and designated CSDNase. CSDNase was purified by (NH 4 ) 2 SO 4 precipitation, Sephacryl S-100 HR gel filtration, weak anion-exchange HPLC, and gel filtration HPLC. The protein was single-chained, with an apparent molecular mass of ca. 34 kDa, as revealed by SDS-PAGE, and an isoelectric point of 7.05, as estimated by isoelectric focusing. CSDNase acted on both double-stranded (ds) and
more » ... ) and single-stranded (ss) DNA, but preferentially on dsDNA. The optimum pH of CSDNase was pH 5.5 and its optimum temperature 55. The activity of CSDNase was not dependent on divalent cations, but its enzymic activity was inhibited by high concentration of the cation: MgCl 2 above 150 mM, MnCl 2 above 200 mM, ZnCl 2 above 150 mM, CaCl 2 above 200 mM, NaCl above 300 mM, and KCl above 300 mM. CSDNase was found to hydrolyze DNA, and to generate 3-phosphate and 5-OH termini. These results indicate that the nucleolytic properties of CSDNase are essentially the same as those of other wellcharacterized acid DNases, and that CSDNase is a member of the acid DNase family. To our knowledge, this is the first report of an acid DNase in a fungus.
doi:10.5483/bmbrep.2004.37.4.466 pmid:15469735 fatcat:mzieuxa25rbc7emanfao3q24bi