PURIFICATION AND CHARACTERIZATION OF A MAMMALIAN ENDOEXONUCLEASE

被引:22
作者
COUTURE, C [1 ]
CHOW, TYK [1 ]
机构
[1] UNIV SHERBROOKE,FAC MED,DEPT NUCL MED & RADIOBIOL,SHERBROOKE J1H 5N4,QUEBEC,CANADA
关键词
D O I
10.1093/nar/20.16.4355
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
An endo-exonuclease has been purified from cultured monkey (CV-1) cells. The enzyme which was purified to near homogeneity to be a 65 kDa monomeric protein. The single-strand DNase activity is endonucleolytic and nonprocessive, whereas the double-strand DNase activity is exonucleolytic and processive. The enzyme was also found to have RNase activity using poly-rA as substrate. The pH optimum for ss-DNase is 8 and for ds-DNase it is 7.5. Both DNase activities require a divalent metal ion (Mg2+, Mn2+, Ca2+, Zn2+) for activity and exhibit the same kinetics of heat inactivation. The purified protein binds to and cleaves a synthetic Holliday junction substrate. The overall enzymatic characteristics of the mammalian protein are very similar to the putative recombination endo-exonucleases purified from Neurospora crassa, Aspergillus nidulans and Saccharomyces cerevisiae.
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页码:4355 / 4361
页数:7
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