title: Characterization of a novel beta-agarase from marine Alteromonas sp. SY37-12 and its degrading products.
abstract: The phenotypic and agarolytic features of an unidentified marine bacteria isolated from the southern ocean of China was studied. The strain was gram-negative, aerobic, and polarly flagellated. It was identified as the genus Alteromonas according to its morphological and physiological characterization. In solid agar, the isolate produced a diffusible agarase that caused agar softening around the colonies. An extracellular agarase was purified by the procedure of ammonium sulfate precipitation, gel filtration on Sephacryl S-100HR, and ion-exchange chromatography on diethylaminoethyl-Sepharose. The purified protein exhibited a single band on SDS-PAGE with a molecular mass of 39.5 kDa. The enzyme hydrolyzed the beta-1,4-glycosidic linkages of agar, yielding neoagarotetraose and neoagarohexaose as the main products. The optimum reaction temperature of the agarase was 35 degrees C, with a narrow range from 30 to 45 degrees C. The enzyme activity reached the maximum at pH 7.0 and in the presence of 2% NaCl. Molecular mass and degrading products showed that the agarase from Alteromonas sp. SY 37-12 was much different from those previously reported.
authors.affiliation: Ocean University of China, Qingdao, 266003, People's Republic of China.
authors.forename: Jingxue
authors.initials: J
authors.lastname: Wang
authors.forename: Haijin
authors.initials: H
authors.lastname: Mou
authors.forename: Xiaolu
authors.initials: X
authors.lastname: Jiang
authors.forename: Huashi
authors.initials: H
authors.lastname: Guan
mesh_terms: D020591:Alteromonas / Q000201:enzymology / Q000378:metabolism*; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D004795:Enzyme Stability; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D009844:Oligosaccharides / Q000032:analysis; D012623:Seawater / Q000382:microbiology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D013696:Temperature; D014871:Water Microbiology
chemical_list: D009844:Oligosaccharides; D006026:Glycoside Hydrolases; C019624:agarase