title: Primary structure and properties of Mn-superoxide dismutase from scallop adductor muscle.
abstract: Manganese-superoxide dismutase was purified to homogeneity from scallop adductor muscle using DEAE-Sephacel, Buthyl-Cellulofine and Superdex 200 pg column chromatographies. The molecular weights of the purified enzyme were calculated to be 22,321.4 according to time-of-flight mass spectrometry, and to be approximately 95,000 and 93,000 on Superdex 200 pg column chromatography and non-denatured PAGE, respectively, and were calculated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be 24,000 and 25,000 in the absence and 25,000 in the presence of beta-mercaptoethanol. These findings suggested that the native enzyme is composed of four identical subunits. Other properties of scallop adductor muscle manganese-superoxide dismutase, including pH stability and heat stability, were also determined. We determined the partial amino acid sequences of purified manganese-superoxide dismutase using digestions by bromocyan and lysyl endopeptidase and also determined the manganese-superoxide dismutase cDNA structure. The amino acid sequence of the enzyme obtained using both methods showed homology to those of vertebrates such as human, bovine, chicken, Xenopus and zebrafish manganese-superoxide dismutases (64.91, 65.35, 64.47, 63.27 and 64.60%, respectively). We also predicted the 3D structure of scallop adductor muscle manganese-superoxide dismutase using molecular operating environment and compared its structure with those of other manganese-superoxide dismutases. The overall structure of scallop adductor muscle manganese-superoxide dismutase was very similar to those of other species, including human and Aspergillus.
authors.affiliation: Department of Molecular Genetics in Medicine, Shiga University of Medical Science, Seta, Otsu 520-2192, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ikebuchi
authors.forename: Keisuke
authors.initials: K
authors.lastname: Takeuchi
authors.forename: Takuya
authors.initials: T
authors.lastname: Yamane
authors.forename: Osamu
authors.initials: O
authors.lastname: Ogikubo
authors.forename: Toshinaga
authors.initials: T
authors.lastname: Maeda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kimura
authors.forename: Iwao
authors.initials: I
authors.lastname: Ohkubo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D008969:Molecular Sequence Data; D049897:Pectinidae / Q000201:enzymology* / Q000235:genetics; D017434:Protein Structure, Tertiary; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D013482:Superoxide Dismutase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification
chemical_list: D013482:Superoxide Dismutase