title: Purification and characterization of a hyperthermostable Mn-superoxide dismutase from Thermus thermophilus HB27.
abstract: Thermostable Mn-dependent catalases are promising enzymes in biotechnological applications. In the present study, a Mn-containing superoxide dismutase of the hyperthermophilic Thermus thermophilus HB27 had been purified and characterized by a two-stage ultrafiltration process after being expressed in E. coli. The enzyme was highly stable at 90°C and retained 57% activity after heat treatment at 100°C for 1 h. The native form of the enzyme was determined as a homotetramer by analytical size exclusion chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The final purified enzyme had an isoelectric point of 6.2 and a high α-helical content of 70%, consistent with the theoretical values. This showed that the purified SOD folded with a reasonable secondary structure.
authors.affiliation: Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266555, People's Republic of China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Liu
authors.forename: Mengmeng
authors.initials: M
authors.lastname: Yin
authors.forename: Hu
authors.initials: H
authors.lastname: Zhu
authors.forename: Jianren
authors.initials: J
authors.lastname: Lu
authors.forename: Zhanfeng
authors.initials: Z
authors.lastname: Cui
mesh_terms: D002942:Circular Dichroism; D004591:Electrophoresis, Polyacrylamide Gel; D005293:Ferritins / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007525:Isoelectric Focusing; D007526:Isoelectric Point; D007700:Kinetics; D008670:Metals / Q000737:chemistry; D008970:Molecular Weight; D017433:Protein Structure, Secondary; D013482:Superoxide Dismutase / Q000737:chemistry / Q000302:isolation & purification*; D013696:Temperature; D016963:Thermus thermophilus / Q000201:enzymology* / Q000235:genetics*
chemical_list: D007477:Ions; D008670:Metals; D005293:Ferritins; D013482:Superoxide Dismutase