title: The complete amino acid sequence and enzymatic properties of an i-type lysozyme isolated from the common orient clam (Meretrix lusoria).
abstract: To determine the structure and functional relationships of invertebrate lysozymes, we isolated a new invertebrate (i)-type lysozyme from the common orient clam (Meretrix lusoria) and determined the complete amino acid sequence of two isozymes that differed by one amino acid. The determined sequence showed 65% similarity to a lysozyme from Venerupis philippinarum (Tapes japonica), and it was therefore classified as an i-type lysozyme. The lytic activities of this lysozyme were similar to those of previously reported bivalve i-type lysozymes, but unlike the V. philippinarum lysozyme, it did not exhibit an increase in activity in high ionic strength. Our data suggest that this lysozyme does not have a dimeric structure, due to the replacement of Lys108 which contributes to dimer formation in the V. philippinarum lysozyme. GlcNAc oligomer activities suggested an absence of transglycosylation activity and a higher number of subsites on this enzyme compared with hen egg lysozyme.
authors.affiliation: Department of Bioscience, School of Agriculture, Tokai University.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kuwano
authors.forename: Kazunari
authors.initials: K
authors.lastname: Yoneda
authors.forename: Yuya
authors.initials: Y
authors.lastname: Kawaguchi
authors.forename: Norie
authors.initials: N
authors.lastname: Araki
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Araki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D049872:Bivalvia / Q000737:chemistry / Q000201:enzymology*; D002645:Chickens / Q000378:metabolism; D004795:Enzyme Stability; D006031:Glycosylation; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D009113:Muramidase / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D009994:Osmolar Concentration; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013379:Substrate Specificity
chemical_list: D007527:Isoenzymes; D009113:Muramidase