title: A novel alpha-amylase from Bacillus mojavensis A21: purification and biochemical characterization.
abstract: alpha-Amylase from Bacillus mojavensis A21 (BMA.2) was purified to homogeneity by ultrafiltration, Sephadex G-75 gel filtration and Sepharose mono Q anion exchange chromatography, with a 15.3-fold increase in specific activity and 11% recovery. The molecular weight of the BMA.2 enzyme was estimated to be 58 kDa by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and gel filtration. The optimum temperature and pH were 80 degrees C and 6.5, respectively. BMA.2 belonged to the EDTA-sensitive alpha-amylase, but its activity was not stimulated by the presence of Ca2+ ions. The major end-products of starch hydrolysis were maltohexaose, maltopentaose and maltotriose. The N-terminal amino acid sequence of the first ten amino acids of the purified alpha-amylase was ASVNGTLMQY. Compared to sequences of other amylases, the ten amino acid sequence contains Val at position 3, while amylases from Bacillus licheniformis NH1 and Bacillus sp. SG-1 have Leu and Thr at position 3, respectively.
authors.affiliation: Laboratoire de Génie Enzymatique et de Microbiologie, Ecole Nationale d'Ingénieurs de Sfax, B.P. "W" 3038, Sfax, Tunisia.
authors.forename: Noomen
authors.initials: N
authors.lastname: Hmidet
authors.forename: Hana
authors.initials: H
authors.lastname: Maalej
authors.forename: Anissa
authors.initials: A
authors.lastname: Haddar
authors.forename: Moncef
authors.initials: M
authors.lastname: Nasri
mesh_terms: D000595:Amino Acid Sequence; D001407:Bacillus / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D002845:Chromatography; D004795:Enzyme Stability; D008969:Molecular Sequence Data; D008970:Molecular Weight; D000516:alpha-Amylases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D000516:alpha-Amylases