Purification and properties of cytosine deaminase from Aspergillus fumigatus
1991; Elsevier BV; Volume: 72; Issue: 4 Linguagem: Inglês
10.1016/0922-338x(91)90161-9
ISSN1872-8073
AutoresTae-Shick Yu, Jae-Kuen Kim, Tohoru Katsuragi, Takuo Sakai, Kenzo Tonomura,
Tópico(s)Peptidase Inhibition and Analysis
ResumoCytosine deaminase (EC 3.5.4.1) from Aspergillus fumigatus IFO 5840, which is the first cytosine deaminase to be found in a mould, was purified 150-fold with an overall yield of 0.75%, to homogeneity judging from disc and SDS-polyacrylamide gel electrophoresis. The enzyme was a monomer of 32 kDa. Besides cytosine, the enzyme stoichiometrically deaminated 5-methylcytosine and 5-fluorocytosine: the activity toward them was 100:28:43, and the apparent Km values for them were 2, 36, and 6.5 mM, respectively. The enzyme had a pH optimum at around pH 7 and temperature optimum at 35°C. The enzyme activity was inhibited by heavy metal ions such as Fe2+, Cu2+, Hg2+, and Pb2+ at 0.1 mM, and by p-chloromercuribenzoate, o-phenanthroline, ATP, and UTP at 1 mM.
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