title: Mass spectrometry based N- and C-terminal sequence determination of a hepatopancreas-type prophenoloxidase from the kuruma prawn, Marsupenaeus japonicus.
abstract: We previously identified and characterized a novel hepatopancreas-type prophenoloxidase from kuruma prawn, Marsupenaeus japonicus. In the characterization, this enzyme was indicated to have a feature of a signal peptide at its N-terminus. The putative primary structure was then proposed but its N- and C-terminal sequences remained undetermined. In the present study, the N- and C-terminal amino acid sequences of this prophenoloxidase were determined by de novo sequencing methods using matrix-assisted laser desorption ionization mass spectrometry. The sequence analyses revealed that the N-terminus of the prophenoloxidase was processed, whereas the C-terminus was not. This finding suggests that this enzyme has a signal peptide, and that it is synthesized at the endoplasmic reticulum in hepatopancreas cells and secreted to hemolymph plasma, similar to the case of hemocyanin, another member of the class III copper proteins.
authors.affiliation: Division of Disease Proteomics, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan. laviebbel@yahoo.co.jp
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kuyama
authors.forename: Taro
authors.initials: T
authors.lastname: Masuda
authors.forename: Chihiro
authors.initials: C
authors.lastname: Nakajima
authors.forename: Kyosuke
authors.initials: K
authors.lastname: Momoji
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Sugawara
authors.forename: Osamu
authors.initials: O
authors.lastname: Nishimura
authors.forename: Takashi
authors.initials: T
authors.lastname: Hirata
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D004156:Catechol Oxidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000201:enzymology; D004792:Enzyme Precursors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D043143:Hepatopancreas / Q000737:chemistry / Q000201:enzymology*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D033561:Penaeidae / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D010449:Peptide Mapping; D017421:Sequence Analysis
chemical_list: D004792:Enzyme Precursors; C038451:pro-phenoloxidase; D004156:Catechol Oxidase