| Literature DB >> 4070306 |
Abstract
We have presented some data from studies of two different DNA cytosine methyltransferases. The first enzyme, M.Hha I, was shown to catalyze 3H exchange from poly(dG.[5-3H]dC), at a rate that is 7 to 10 times greater than the rate of methylation. The exchange is inhibited by AdoHcy in an uncompetitive fashion. This pattern of inhibition suggests an ordered reaction sequence for M.Hha I catalyzed methylation. The second enzyme, M.Hpa II, was demonstrated to make an irreversible adduct with azaC-DNA. The results provide evidence that both enzymes form covalent dihydropyrimidine intermediates during catalysis.Entities:
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Year: 1985 PMID： 4070306
Source DB: PubMed Journal: Prog Clin Biol Res ISSN： 0361-7742