Purification and Properties of the Catalase of Bakers’ Yeast

Catalase from bakers’ yeast has been purified to homogeneity in the analytical ultracentrifuge and in gel electrophoresis; sedimentation measurements permit an estimation of its molecular weight as 248,000. Under denaturing conditions, polyacrylamide gel electrophoresis revealed dissociation of a major component of molecular weight 61,000, which constituted 90% of the total protein of the stained gel, suggesting that the native enzyme is tetrameric. The iron content was 0.096%, corresponding to a subunit molecular weight of 58,000. Specific activity was high (Kat. f . = 66,000); catalytic and spectroscopic properties were similar to those of catalases from other species. The enzyme is present in commercial yeast and in a variety of haploid and diploid wild type strains.