%0 Journal Article
%T Further purification and characterization of human 3-methyladenine-DNA glycosylase. Evidence for broad specificity.
%A Gallagher PE
%A Brent TP
%J Biochim Biophys Acta
%V 782
%N 4
%D Sep 1984 10
%M 6477916
暂无%R 10.1016/0167-4781(84)90045-9
%X Further purification of a human placental 3-methyladenine-DNA glycosylase by phosphocellulose column chromatography yielded a 6000-fold increase in specific activity with greater than 5% recovery. Although 3-methyladenine was the predominant base released from double-stranded methylated DNA by this enzyme, minor releasing activities for 7-methylguanine and 3-methylguanine were also observed. During purification, the three DNA glycosylase activities consistently copurified with constant ratios of specific activity. Moreover, all the activities were heat-inactivated at 50 degrees C at the same rate, required double-stranded methylated DNA as substrate, were inhibited by spermine and spermidine, and were not subject to product inhibition. These data strengthen the likelihood that the three activities are associated with a single DNA glycosylase.