[Physico-chemical characteristics of catalases from Micrococcus sp. n]

The physico-chemical properties of heme-containing and non-heme catalases isolated from the cell culture of Micrococcus sp. n. grown under intensive aeration were studied. The enzyme preparations were homogenous during polyacrylamide disc electrophoresis. The spectral and functional properties of the enzymes (e. g. specific activity, subunit molecular weight, quaternary structure, amino acid composition, immunoprecipitability, N-terminal amino acid sequences) were investigated. Monocrystals of non-heme catalase applicable for an X-ray analysis were grown and examined by X-ray spectroscopy. Both enzymes were stable upon storage in 40% ammonium sulfate for 2 months and resistant to lyophylization without any significant loss of their activity. Non-heme catalase is apparently an independent enzyme which is not derived from heme-containing catalase via dissociation, limited proteolysis or heme cleavage.