- All four known cyclic adducts formed in DNA by the vinyl chloride metabolite chloroacetaldehyde are released by a human DNA glycosylase. Dosanjh, M.K., Chenna, A., Kim, E., Fraenkel-Conrat, H., Samson, L., Singer, B. Proc. Natl. Acad. Sci. U.S.A. (1994)