title: [Purification and characterization of a bromoperoxidase from Gracilaria lemaneiformis].
abstract: A bromoperoxidase from Gracilaria lemaneiformis was purified to homogeneity using a multi-step process of ammonium sulfate precipitation (AS), dialysis, and DEAE-cellulose 52 anion exchange chromatography. The bromoperoxidase activity was unstable or undetectable in crude extract solution. However, it became stable with electrophoretic purity after this multiple purification process. The anion exchange chromatography purification was a critical step in the purification process, which effectively eliminated the phycobiliprotein and smucilaginous polysaccharides. The purified bromoperoxidase was a monomeric enzyme with the relative molecular masses of 66 kD as determined by denaturing and native gradient gel electrophoresis. The optimal pH for bromoination was 6.0 and bromoperoxidase activity was stable as stored at a broad pH range of 3.0-9.0. Of a range of compounds tested, only vanadium enhanced bromoperoxidase activity. Kinetic studies for the bromination of monochlorodimedone (MCD) showed that the Km values of Br- and H2O2 are 53.5 micromol/L, 38 micromol/L respectively.
authors.affiliation: Marine Bioproducts Engineering Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Jin
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Xingju
authors.initials: X
authors.lastname: Yu
authors.forename: Jinyou
authors.initials: J
authors.lastname: Zhang
authors.forename: Peichun
authors.initials: P
authors.lastname: Wu
mesh_terms: D002852:Chromatography, Ion Exchange / Q000379:methods; D004795:Enzyme Stability; D044724:Gracilaria / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010544:Peroxidases / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D010544:Peroxidases; C026195:bromide peroxidase