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Purification and characterization of catalase-1 from Bacillus subtilis

1987; NRC Research Press; Volume: 65; Issue: 11 Linguagem: Inglês

10.1139/o87-122

1208-6002

P.C. Loewen, Jacek Switala,

Enzyme function and inhibition

The catalase activity produced in vegetative Bacillus subtilis, catalase-1, has been purified to homogeneity. The apparent native molecular weight was determined to be 395 000. Only one subunit type with a molecular weight of 65 000 was present, suggesting a hexamer structure for the enzyme. In other respects, catalase-1 was a typical catalase. Protoheme IX was identified as the heme component on the basis of the spectra of the enzyme and of the isolated hemochromogen. The ratio of protoheme/subunit was 1. The enzyme remained active over a broad pH range of 5–11 and was only slowly inactivated at 65 °C. It was inhibited by cyanide, azide, and various sulfhydryl compounds. The apparent K m for hydrogen peroxide was 40.1 mM. The amino acid composition was typical of other catalases in having relatively low amounts of tryptophan and cysteine.