abstract:Catalase plays important roles in antioxidation and cell signaling. One cDNA (1794bp, DQ021914) encoding the putative catalase was cloned from Antrodia camphorata. The deduced amino acid sequence is conserved among the reported catalases. To characterize the A. camphorata catalase, the coding region was subcloned into a vector pET-20b(+) and transformed into E. coli. The recombinant 6His-tagged catalase was expressed and purified by Ni(superscript 2+)-nitrilotriacetic acid sepharose. The purified enzyme showed one band by 10% SDS-PAGE. The enzyme retained 50% activity at 60℃ for 14 min. The enzyme was active under a broad pH range from 7.8 to 11.2. The enzyme showed 67% activity after 4h of incubation at 37℃ with trypsin. It was also proven able to protect intact supercoiled plasmid DNA from •OH-induced nicking. Study of the enzyme's properties may prove beneficial for future applications in medicine or health food.