Isolation, purification, and characterization of a neutral Mg(2+)-dependent deoxyribonuclease of the Colorado potato beetle Leptinotarsa decemlineata Say.
A neutral Mg(2+)-dependent deoxyribonuclease from the Colorado potato beetle was isolated and characterized in physicochemical terms. An electrophoretically homogeneous preparation of the enzyme was obtained using salt fractionation, Sephadex G-100 gel filtration, and subsequent preparative isoelectrofocusing in an Ultrodex layer. The molecular weight of the purified DNase preparation (with a purification degree of 104) and its isoelectric point were 100 kD and 9.1, respectively. The enzyme activity was maximal at pH 7.2 and 46 degrees C in the presence of 10 mM Mg2+. The DNase of the Colorado beetle preferentially hydrolysed denatured DNA via the endonuclease pathway, degrading the substrate to oligonucleoside-3'-phosphates. As far as the physical and chemical properties are concerned, this Colorado beetle DNase seems different from previously investigated DNases of other insect species.
Borodin
S A
SA
Department of Organic and Biological Chemistry, Moscow State Pedagogical University, Russia.
Konichev
A S
AS
D000818:Animals; D002850:Chromatography, Gel; D001517:Coleoptera / Q000201:enzymology*; D004247:DNA / Q000737:chemistry; D003851:Deoxyribonucleases / Q000302:isolation & purification* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D007525:Isoelectric Focusing; D008274:Magnesium / Q000378:metabolism*; D009691:Nucleic Acid Denaturation
D004247:DNA; D003851:Deoxyribonucleases; D008274:Magnesium