PURIFICATION AND CHARACTERIZATION OF CATALASE FROM GOAT (CAPRA-CAPRA)LUNG

Catalase plays a major role in the protection of tissues from toxic ef fects of H2O2 and partially reduced oxygen species. In the present stu dy catalase was extracted and purified 330-fold from goat lung by acet one fractionation and successive chromatographies on DEAE-cellulose, S ephadex G-200, Blue Sepharose CL-6B and Ultrogel AcA-34. The purified enzyme was almost homogeneous as judged by polyacrylamide gel electrop horesis and FPLC. The molecular weight and Stokes' radius of the purif ied enzyme were 339 kDa and 127 +/- 2 Angstrom. The enzyme had 11 sulf hydryl groups and 15 tryptophan groups per mol of the enzyme. A broad pH optimum in the range 5.2 to 7.8 was obtained. Sulfhydryl group bind ing agents, thiol reagents and N-Bromosuccinimide inhibited the enzyme activity. The kinetic data show no cooperativity between the substrat e binding sites. Tryptophan, indole acetic acid, cysteine, formaldehyd e and sodium azide inhibited the enzyme non-competitively with K-i val ues of 1.5, 1.6, 6.7, 0.55 and 0.0017 mM, respectively.