title: A small chimerically bifunctional monomeric protein: Tapes japonica lysozyme.
abstract: The lysozyme of the marine bilave Tapes japonica (13.8 kDa) is a novel protein. The protein has 46% homology with the destabilase from medicinal leech that has isopeptidase activity. Based on these data, we confirmed hydrolysis activity of T. japonica lysozyme against three substrates: L-gamma-Glu-pNA, D-gamma-Glu-pNA, and epsilon-(gamma-Glu)-L-Lys. The optimal pH of chitinase and isopeptidase activity was 5.0 and 7.0, respectively. The isopeptidase activity was inhibited with serine protease inhibitor, but the lytic and chitinase activities were not. Moreover, only isopeptidase activity is decreased by lyophilization, but lytic and chitinase activities were not. We conclude that T. japonica lysozyme expresses isopeptidase and chitinase activity at different active sites.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Takeshita
authors.forename: Y
authors.initials: Y
authors.lastname: Hashimoto
authors.forename: T
authors.initials: T
authors.lastname: Ueda
authors.forename: T
authors.initials: T
authors.lastname: Imoto
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002688:Chitinases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D008970:Molecular Weight; D008974:Mollusca / Q000201:enzymology*; D009113:Muramidase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017433:Protein Structure, Secondary; D016415:Sequence Alignment
chemical_list: D004791:Enzyme Inhibitors; D002688:Chitinases; D009113:Muramidase