Portland State University. Department of Biology
Mary L. Taylor
Term of Graduation
Date of Publication
Master of Science (M.S.) in Biology
Catalase, Enterococcus faecalis
1 online resource (vii, 61 pages)
Catalase is an important biological enzyme that most organisms employ during aerobic growth to catalyze the decomposition of hydrogen peroxide, a toxic reduction product of oxygen, into water and molecular oxygen. Traditionally, the bacterium Enterococcus faecal is is considered to have no cytochrome system and to be catalase negative. However, certain strains of E. subsequent studies have shown that faecalis are capable of producing catalase when grown aerobically in a medium containing hematin.
The goals of this study were to purify and characterize catalase from a clinical strain of E. faecalis. The organisms were grown under aerobic conditions in a hematin supplemented medium. The catalase 2 of E. faecalis was purified to homogeneity with procedure that yielded a final 120-fold purification and a recovery of 17% of the original activity. The apparent native molecular weight was found to be 250,000±10,000 daltons, and only one subunit type with a molecular weight of 64,000±2000 daltons was present. The purified catalase shows pH optima from 6.0 to 7.8. The optical spectrum exhibits an absorption peak at 406nm. The enzyme is sensitive to the heme poison azide and contains iron, a typical property of the heme catalase. The purified catalase from E. faecalis characterized in this study is a typical heme-iron catalase, rather than an atypical nonheme pseudocatalase which contains manganese. Thus, the catalase of E. faecalis is similar to most of other typical catalase enzymes in many important characteristics. This study of catalase from E. faecalis may provide knowledge necessary to investigate the mapping and cloning of the gene encoding the catalase enzyme.
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Zhu, Zhenghong, "Purification and Characterization of Catalase From Enterococcus Faecalis" (1997). Dissertations and Theses. Paper 6281.