title: IDENTIFICATION AND CHARACTERIZATION OF THE CATALASE GENE PyCAT FROM THE RED ALGA PYROPIA YEZOENSIS (BANGIALES, RHODOPHYTA)(1).
abstract: Catalase is an antioxidant enzyme that plays a significant role in protection against oxidative stress by reducing hydrogen peroxide. The full-length catalase cDNA sequence as isolated from expressed sequence tags (ESTs) of Pyropia yezoensis (Ueda) M. S. Hwang et H. G. Choi (PyCAT) through rapid amplification of cDNA ends (RACE) was identified and characterized. It encoded a polypeptide of 529 amino acids, which shared 36%-44% similarity with other known catalase proteins. Phylogenetic analysis revealed that PyCAT was closer to the catalases from plants than from other organisms. The PyCAT mRNA expression was investigated using real-time PCR to determine life-cycle-specific expression and the expression pattern during desiccation. The mRNA expression level in gametophytes was significantly higher than in sporophytes, and the mRNA expression level of PyCAT was significantly up-regulated during the desiccation process. The recombinant PyCAT protein was purified and analyzed biochemically. The recombinant PyCAT protein exhibited high enzymatic activity (28,000 U·mg(-1) ) with high thermal stability and a broad pH range. All these results indicate that the PyCAT is a typical member of the plant and algal catalase family and may play a significant role in minimizing the effect of oxidative damage in P. yezoensis during desiccation.
authors.affiliation: College of Marine Life Science, Ocean University of China, Qingdao 266003, ChinaGuangxi Mangrove Research Center, Beihai 536000, ChinaCollege of Marine Life Science, Ocean University of China, Qingdao 266003, China.
authors.forename: Xian C
authors.initials: XC
authors.lastname: Li
authors.affiliation: College of Marine Life Science, Ocean University of China, Qingdao 266003, ChinaGuangxi Mangrove Research Center, Beihai 536000, ChinaCollege of Marine Life Science, Ocean University of China, Qingdao 266003, China.
authors.forename: Yong Z
authors.initials: YZ
authors.lastname: Xing
authors.affiliation: College of Marine Life Science, Ocean University of China, Qingdao 266003, ChinaGuangxi Mangrove Research Center, Beihai 536000, ChinaCollege of Marine Life Science, Ocean University of China, Qingdao 266003, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Jiang
authors.affiliation: College of Marine Life Science, Ocean University of China, Qingdao 266003, ChinaGuangxi Mangrove Research Center, Beihai 536000, ChinaCollege of Marine Life Science, Ocean University of China, Qingdao 266003, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Qiao
authors.affiliation: College of Marine Life Science, Ocean University of China, Qingdao 266003, ChinaGuangxi Mangrove Research Center, Beihai 536000, ChinaCollege of Marine Life Science, Ocean University of China, Qingdao 266003, China.
authors.forename: Hai L
authors.initials: HL
authors.lastname: Tan
authors.affiliation: College of Marine Life Science, Ocean University of China, Qingdao 266003, ChinaGuangxi Mangrove Research Center, Beihai 536000, ChinaCollege of Marine Life Science, Ocean University of China, Qingdao 266003, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Tian
authors.affiliation: College of Marine Life Science, Ocean University of China, Qingdao 266003, ChinaGuangxi Mangrove Research Center, Beihai 536000, ChinaCollege of Marine Life Science, Ocean University of China, Qingdao 266003, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhou
keywords: Pyropia yezoensis; RACE; Rhodophyta; catalase; desiccation; enzyme activity; life cycle; mRNA expression