RT Journal Article SR Electronic(1) A1 Kim, Hyoung-pyo A1 Lee, Jong-Soo A1 Hah, Yung Chil A1 Roe, Jung-HyeYR 1994 T1 Characterization of the major catalase from Streptomyces coelicolorATCC 10147 JF Microbiology, VO 140 IS 12 SP 3391 OP 3397 DO https://doi.org/10.1099/13500872-140-12-3391 PB Microbiology Society, SN 1465-2080, AB Streptomyces coelicolorATCC 10147 produced catalases whose electrophoretic mobility varied depending on the growth phase in liquid culture. Polyacrylamide gel electrophoresis of cell extracts resulted in six catalase activity bands, which were designated Cat1 to Cat6. Of these. Cat4 appeared during all growth phases, whereas Cat1 appeared only during the stationary phase. Catalase-deficient mutants were screened by the H2O2bubbling test following NTG mutagenesis. In all the non-bubbling mutants tested, the Cat4 activity band significantly decreased or disappeared, suggesting that Cat4 is the major catalase. Cat4 was purified to electrophoretic homogeneity and some of its properties analysed. The enzyme has a native molecular mass of 225 kDa, as determined by gel permeation column chromatography, and consists of four identical subunits of 57 kDa, as determined by SDS-PAGE. The enzyme contains 2.6 molecules of protohaem IX per tetramer, as indicated by the absorption spectrum. It was not reducible by sodium dithionite and exhibited no peroxidase activity with o-dianisidine as the substrate. All these characteristics, as well as inhibitor studies, indicate that the major vegetative catalase in S. coelicolor, unlike E. colivegetative catalase, is a member of the typical monofunctional catalases found in eukaryotes and some bacteria., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/13500872-140-12-3391