title: Purification and characterization of a bifunctional alginate lyase from Pseudoalteromonas sp. SM0524.
abstract: An alginate lyase-producing bacterial strain, Pseudoalteromonas sp. SM0524, was screened from marine rotten kelp. In an optimized condition, the production of alginate lyase from Pseudoalteromonas sp. SM0524 reached 62.6 U/mL, suggesting that strain SM0524 is a good producer of alginate lyases. The bifunctional alginate lyase aly-SJ02 secreted by strain SM0524 was purified. Aly-SJ02 had an apparent molecular mass of 32 kDa. The optimal temperature and pH of aly-SJ02 toward sodium alginate was 50 °C and 8.5, respectively. The half life period of aly-SJ02 was 41 min at 40 °C and 20 min at 50 °C. Aly-SJ02 was most stable at pH 8.0. N-terminal sequence analysis suggested that aly-SJ02 may be an alginate lyase of polysaccharide lyase family 18. Aly-SJ02 showed activities toward both polyG (α-l-guluronic acid) and polyM (β-D-mannuronic acid), indicating that it is a bifunctional alginate lyase. Aly-SJ02 had lower K(m) toward polyG than toward polyM and sodium alginate. Thin layer chromatography and ESI-MS analyses showed that aly-SJ02 mainly released dimers and trimers from polyM and alginate, and trimers and tetramers from polyG, which suggests that aly-SJ02 may be a good tool to produce dimers and trimers from alginate.
authors.affiliation: State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Jinan 250100, China. sdnyljw@163.com
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Li
authors.forename: Sheng
authors.initials: S
authors.lastname: Dong
authors.forename: Jie
authors.initials: J
authors.lastname: Song
authors.forename: Chun-Bo
authors.initials: CB
authors.lastname: Li
authors.forename: Xiu-Lan
authors.initials: XL
authors.lastname: Chen
authors.forename: Bin-Bin
authors.initials: BB
authors.lastname: Xie
authors.forename: Yu-Zhong
authors.initials: YZ
authors.lastname: Zhang
mesh_terms: D000464:Alginates / Q000378:metabolism*; D000595:Amino Acid Sequence; D020723:Glucuronic Acid / Q000378:metabolism; D006603:Hexuronic Acids / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D044423:Kelp / Q000382:microbiology*; D007700:Kinetics; D008969:Molecular Sequence Data; D011133:Polysaccharide-Lyases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D031161:Pseudoalteromonas / Q000201:enzymology* / Q000302:isolation & purification; D054712:Salinity; D013696:Temperature
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D011133:Polysaccharide-Lyases; C016158:poly(beta-D-mannuronate) lyase