Catalysis of the reaction: DNA containing 7-methylguanine + H2O = DNA with abasic site + 7-methylguanine. This reaction is the hydrolysis of DNA by cleavage of the N-C1' glycosidic bond between the damaged DNA 7-methylguanine and the deoxyribose sugar to remove the 7-methylguanine, leaving an abasic site.
DNA-7-methylguanine glycosylase activity