| Title | Purification and Characterization of Catalase-3 of Deinococcus radiophilus |
|---|---|
| Author | Lee, In Jeong · Lee, Young Nam * |
| Address | Department of Microbiology, College of Natural Sciences, Chungbuk National University |
| Bibliography | Journal of Microbiology, 33(3),239-243, 1995, |
| DOI | |
| Key Words | Deinococcus radiophilus, UV resistant, catalase, isoenzymes, reactive oxygen species |
| Abstract | Deinococcus radiophilus, an UV resistant bacterium seemed to contain three issoenzymes of catalase. Among them, the samllest and most abundant species in cell-free extract, catalase-3 which also exhibited peroxidase activity was purified to electrophoretic homogeneity (145-fold purification) by chromatographic procedures. Its molecular weight was 155 kDa composed of four 38 kDa subunits. The K_m value of catalase-3 for H₂O₂was approximately 0.5 mM. This enzyme showed a typical ferric heme spectrum with maximum absorption at 405 nm. Upon binding to cyanide, the 405 nm peak shifted to 420 nm. Catalase-3 was very sensitive to inhibitors of heme proteins, such as cyanide, azide and hydroxylamine. A ratio of A_405/A_28O was 0.5 Catalase-3 was active over a wide range of pH, between pH 7 and 10. The enzyme was rather heat-labile and partially sensitive to ethanol-chloroform treatment, but resistant to 3-amino-1, 2, 4-triazole. Catalase-3 of D. radiophilus, which is a bifunction catalatic peroxidatic enzyme seemed to share certain molecular properties with the typical catalase and the catalase-peroxidase along with its own unique features. |
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