Abstract
Catalase was purified from the Gram-positive bacterium Streptomyces coelicolor A3(2) in a three-step purification procedure comprising (NH4)2SO4, fractionation, Phenyl-Sepharose chromatography and Mono Q chromatography. The purification of catalase, as judged by the final specific activity of 110000 U mg-1 was 250-fold with a 35% yield. The native protein was a homotetramer with a subunit Mr 55000. N-terminal and internal peptide sequence analyses showed that there was a high degree of sequence similarity between the S. coelicolor catalase and other microbial and mammalian catalases. Southern blot analysis indicated that there was a single catalase gene in S. coelicolor. The specific activity of catalase throughout the growth of batch cultures was investigated and elevated catalase activity was found in stationary-phase cells.