%0 Journal Article
%T Human lymphoblasts contain DNA glycosylase activity excising N-3 and N-7 methyl and ethyl purines but not O6-alkylguanines or 1-alkyladenines.
%A Singer B
%A Brent TP
%J Proc Natl Acad Sci U S A
%V 78
%N 2
%D Feb 1981
%M 6940152
%F 12.779
%R 10.1073/pnas.78.2.856
%X Cultured human lymphoblasts (CCRF-CEM line) have DNA glycosylase activities, the specificities of which were investigated by using high-performance liquid chromatography. In addition to 3-methyladenine, 3-ethyladenine, 7-methylguanine, 7-ethylguanine, 3-methylguanine, and 3-ethylguanine also were excised from alkylated double-stranded DNA and deoxypolynucleotides, but 1-methyladenine, 1-ethyladenine, O6-methylguanine, and O6-ethylguanine were not. The glycosylase activity was generally greater for the methylated than for the corresponding ethylated purines and was also greater toward 3-alkyladenine than toward 3-alkyladenine than toward 3-alkylguanine. 7-Methylguanine and 7-ethylguanine were excised to similar but low extents. However, in molar terms, the release of 7-methylguanine was similar to that of 3-methyladenine.