title: Primary structure of bovine lactoperoxidase, a fourth member of a mammalian heme peroxidase family.
abstract: Much is known about bovine lactoperoxidase but no data are available on its primary structure. In this work its main active fraction was isolated from cow's milk and sequenced using a conventional strategy. A clear similarity was found with human myeloperoxidase, eosinophil peroxidase and thyroperoxidase, the sequences of which were recently elucidated from those of their cDNAs and/or genes. The single peptide chain of bovine lactoperoxidase contains 612 amino acid residues, including 15 half-cystines and 4 or 5 potential N-glycosylation sites. The corresponding peptide segments of human myeloperoxidase, eosinophil peroxidase and thyroperoxidase display 55%, 54% and 45% identity with bovine lactoperoxidase, respectively, with 14 out of the 15 half-cystines present in each of the four enzymes being located in identical positions. The occurrence of an odd number of half-cystines in bovine lactoperoxidase supports the recent finding of a heme thiol released from this enzyme by a reducing agent, suggesting that the heme is bound to the peptide chain via a disulfide linkage, since the absence of free thiol in the enzyme was reported long ago.
authors.affiliation: Protein Unit, Institut National de la Recherche Agronomique, Jouy-en-Josas, France.
authors.forename: M M
authors.initials: MM
authors.lastname: Cals
authors.forename: P
authors.initials: P
authors.lastname: Mailliart
authors.forename: G
authors.initials: G
authors.lastname: Brignon
authors.forename: P
authors.initials: P
authors.lastname: Anglade
authors.forename: B R
authors.initials: BR
authors.lastname: Dumas
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D007784:Lactoperoxidase / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000302:isolation & purification; D010449:Peptide Mapping; D010544:Peroxidases / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
chemical_list: D010446:Peptide Fragments; D007784:Lactoperoxidase; D010544:Peroxidases