Two different proteases produced by a deep-sea psychrotrophic bacterial strain, Pseudoaltermonas sp. SM9913
ABSTRACT A psychrotrophic bacterial strain, Pseudoaltermonas sp. SM9913, was isolated from deep-sea sediment collected at 1,855m depth. Two proteases produced by Pseudoaltermonas sp. SM9913 were purified, MPC-01 and MCP-02. MCP-01 is a serine protease with a molecular weight of 60.7kDa. It is cold-adapted with an optimum temperature of 30–35C. Its Km and Ea for the hydrolysis of casein were 0.18% and 39.1kJ mol–1, respectively. It had low thermostability, and its activity was reduced by 73% after incubation at 40C for 10min. MCP-02 is a mesophilic metalloprotease with a molecular weight of 36kDa. Its optimum temperature for the hydrolysis of casein was 50–55C. The Km and Ea of MCP-02 for the hydrolysis of casein were 0.36% and 59.3kJ mol–1, respectively. MCP-02 had high thermostability, and its activity was reduced by only 30.5% after incubation at 60C for 10min. At low temperatures, Pseudoaltermonas sp. SM9913 mainly produced the psychrophilic protease MCP-01.
Article: Purification and characterization of a bifunctional alginate lyase from Pseudoalteromonas sp. SM0524.[show abstract] [hide abstract]
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.Marine Drugs 01/2011; 9(1):109-23. · 3.85 Impact Factor