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Cytidine deaminase activity in Penicillium politans NRC‐510
Author(s) -
Elshafei Ali M.,
Ali Nadia H.,
Mohamed Latifa A.
Publication year - 2005
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.200510575
Subject(s) - cytidine deaminase , chemistry , microbiology and biotechnology , biochemistry , biology , enzyme
Cell‐free extracts of nitrate‐grown Penicillium politans NRC‐510 catalyzes the hydrolytic deamination of cytidine to uridine. Uridine was chromatographically identified in cell‐free extracts. The enzyme exhibited optimum pH and temperature activities at 6.5 and 80 °C respectively. Thermal stability experiments indicated that the enzyme restored its activity at 80 °C for at least 60 minutes. When cell‐free extracts were incubated at 90 °C for 5 minutes enzyme activity was inhibited by about 33%. The involvement of sulfhydryl group(s) in the catalytic site of the enzyme was shown. HgCl 2 (5 × 10 –3 M ) and CuSO 4 (10 –2 M ) caused a complete inhibition of enzyme activity. Ethylene diamine tetraacetate at a concentration of 5 × 10 –3 M and 10 –2 M inhibited the enzyme as well. Whereas, MgCl 2 , CoSO 4 and MnCl 2 had a remarkable activating effect. Dialysis of the cell‐free extracts resulted to an increase in enzyme activity by about 30%. To our knowledge the thermophilic nature of the cytidine deaminase of P. politans NRC‐510 is unique. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)