Purification and characterization of a catalase from the liver of bullfrog, Rana catesbeiana Shaw

A catalase was purified from the liver of bullfrog, Rana catesbeiana Shaw, after extraction, ammonium sulfate precipitations, DEAE-Sephadex A-50 chromatography, gel filtration chromatography on a Sephadex G-150 column, ion exchange chromatography on a DEAE-Sephacel column and Sephacryl S-300 column. The yield and purification from the starting crude extract were 0.25% and 73.57-fold, respectively. The purified catalase with an apparent molecular mass of 186 kDa was shown to be composed of four identical subunits of apparent molecular mass of 47.7 kDa. The purified catalase is active over a broad pH range of 6.0-10.0, and it has an isoelectric point of 6.3. The enzyme showed a K-m for H2O2 of 20 mM and an apparent V-max of 51.91 U/mg, and its maximum absorption was at 408 nm in the visible portion of the spectrum. In addition, the purified enzyme was markedly inhibited by azide, cyanide and hydroxylamine.