title: Purification and characterization of a new alginate lyase from a marine bacterium Vibrio sp.
abstract: An alginate lyase-producing bacterial strain, Vibrio sp. QY105, was isolated from sea mud of Qingdao. It secreted 90 % of total enzyme activity within the first 20 h of fermentation. An alginate lyase, AlyV5, with an apparent MW of 37 kDa and a specific activity of 2152 U/mg was purified from the culture supernatant. It was most active at 38 °C and pH 7.0 in 20 mM Tris/HCl. The enzyme was stable over a broad pH range (6.0-9.0) and retained ~40 % activity after holding at 90 °C for 10 min. AlyV5 showed activities towards both polyguluronate and polymannuronate, but degraded the former more efficiently. AlyV5 mainly produced disaccharide, trisaccharide and tetrasaccharide from polyguluronate, trisaccharide, tetrasaccharide and pentasaccharide from polymannuronate.
  
  
  OBJECTIVE
  The purpose of this study is to find a polyG-preference alginate lyase for the saccharification of alginate combined with our polyM-preference alginate lyases.
authors.affiliation: Key Laboratory of Marine Drugs, Chinese Ministry of Education, Ocean University of China, Qingdao 266003, China. wangya62656@163.com
authors.forename: Ya
authors.initials: Y
authors.lastname: Wang
authors.forename: En-Wen
authors.initials: EW
authors.lastname: Guo
authors.forename: Wen-Gong
authors.initials: WG
authors.lastname: Yu
authors.forename: Feng
authors.initials: F
authors.lastname: Han
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D011133:Polysaccharide-Lyases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D012965:Sodium Chloride; D013379:Substrate Specificity; D013696:Temperature; D014733:Vibrio / Q000737:chemistry / Q000201:enzymology*; D014871:Water Microbiology
chemical_list: D001426:Bacterial Proteins; D012965:Sodium Chloride; D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase