Inactivation of Blasticidin S by Bacillus cereus. V. Purification and Characterization of Blasticidin S-Deaminase Mediated by a Plasmid from Blasticidin S Resistant Bacillus cereus K55-S1

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Blasticidin S (BS) deaminase (BSR) from a BS-resistant strain, Bacillus cereus K55-S1,was purified to homogeneity. Molecular weights determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and by gel filtration on HPLC are about 15500 and 35000,respectively, indicating the enzyme is a homodimer. The amino acid composition and N-terminal sequence of BSR are the same as those deduced from the nucleotide sequence of the BS-resistant gene, bsr. The optimum temperature and pH for enzyme activity are 60-65℃ and near 10.0,respectively. The activity of BSR is inhibited by Cu^<2+>, Hg^<2+>, and p-chloromercuric benzoate (PCMB). Inhibition by PCMB or HgCl_2 is reversible by the addition of SH reagents. The enzyme catalyzes the deamination of BS and its derivatives, but not cytosine nucleosides.
社団法人日本薬学会の論文
1995-02-15