著者

Hayakawa Hiroshi Kumura Keiko Sekiguchi Mutsuo

出版者

社団法人 日本生化学会

雑誌

The Journal of Biochemistry (ISSN:0021924X)

巻号頁・発行日

vol.84, no.5, pp.1155-1164, 1978

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Uracil-DNA glycosylase, which acts specifically on uracil-containing DNA, was purified 250-fold from an extract of <i>Escherichia coli</i> 1100. The enzyme releases free uracil from DNA, producing alkali-labile apyrimidinic sites in the DNA. The enzyme is active on both native and heat-denatured DNA of phage PBS1, which contains uracil in place of thymine. &phi;X174 DNA which had been treated with bisulfite and then at alkaline pH was susceptible to the action of uracil-DNA glycosylase. Since DNA treated with bisulfite alone was less susceptible to the enzyme, it is likely that the enzyme recognizes deaminated cytosine, namely uracil, but not bisulfite adducts of uracil and cytosine in the treated DNA. DNA treated with nitrite or hydroxylamine was not attacked by the enzyme. Enzyme activity acting on bisulfite-treated DNA was absent from an extract of <i>E. coli</i> mutant BD10 (<i>ung</i>). The mutant exhibited higher sensitivity to bisulfite than did the wild-type strain and was unable to reactivate phage T1 pre-exposed to bisulfite and weak alkali.