title: The brown algal kelp Laminaria digitata features distinct bromoperoxidase and iodoperoxidase activities.
abstract: Different haloperoxidases, one specific for the oxidation of iodide and another that can oxidize both iodide and bromide, were separated from the sporophytes of the brown alga Laminaria digitata and purified to electrophoretic homogeneity. The iodoperoxidase activity was approximately seven times more efficient than the bromoperoxidase fraction in the oxidation of iodide. The two enzymes were markedly different in their molecular masses, trypsin digestion profiles, and immunological characteristics. Also, in contrast to the iodoperoxidase, bromoperoxidases were present in the form of multimeric aggregates of near-identical proteins. Two full-length haloperoxidase cDNAs were isolated from L. digitata, using haloperoxidase partial cDNAs that had been identified previously in an Expressed Sequence Tag analysis of the life cycle of this species (1). Sequence comparisons, mass spectrometry, and immunological analyses of the purified bromoperoxidase, as well as the activity of the protein expressed in Escherichia coli, all indicate that these almost identical cDNAs encode bromoperoxidases. Haloperoxidases form a large multigenic family in L. digitata, and the potential functions of haloperoxidases in this kelp are discussed.
authors.affiliation: UMR 1931, CNRS-Laboratoires Goëmar, Station Biologique, BP 74, F-29682 Roscoff Cedex, France.
authors.forename: Carole
authors.initials: C
authors.lastname: Colin
authors.forename: Catherine
authors.initials: C
authors.lastname: Leblanc
authors.forename: Elsa
authors.initials: E
authors.lastname: Wagner
authors.forename: Ludovic
authors.initials: L
authors.lastname: Delage
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Leize-Wagner
authors.forename: Alain
authors.initials: A
authors.lastname: Van Dorsselaer
authors.forename: Bernard
authors.initials: B
authors.lastname: Kloareg
authors.forename: Philippe
authors.initials: P
authors.lastname: Potin
mesh_terms: D000595:Amino Acid Sequence; D018076:DNA, Complementary / Q000302:isolation & purification; D019281:Dimerization; D007453:Iodide Peroxidase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D007454:Iodides / Q000378:metabolism; D007795:Laminaria / Q000201:enzymology*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010449:Peptide Mapping; D010544:Peroxidases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D011487:Protein Conformation; D016415:Sequence Alignment
chemical_list: D018076:DNA, Complementary; D007454:Iodides; D010544:Peroxidases; C026195:bromide peroxidase; D007453:Iodide Peroxidase