A thermo-stable lysine aminopeptidase from Pseudomonas aeruginosa: Isolation, purification, characterization, and sequence analysis

作者：Wu, Yan Tao; Zhou, Nan Di; Zhou, Zhe Min; Gao, Xin Xing; Tian, Ya Ping^*

来源：Journal of Basic Microbiology, 2014, 54(10): 1110-1119.

DOI：10.1002/jobm.201300752

• Aminopeptidase
• Pseudomonas aeruginosa
• NJ-814
• Purification
• Characterization
• Sequence analysis

Pseudomonas aeruginosa NJ-814, isolated from garden soil, produced an extracellular aminopeptidase that was purified using ammonium sulfate precipitation and ion exchange chromatography. The purity was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the M-r value of the enzyme was estimated to be 55kDa. The purified enzyme shows maximum activity at pH 9.0 and 80 degrees C. It exhibits high thermo-stability. Half of the activity can remain after incubation at 80 degrees C for 119min. It is stable within pH range of 7.5-10.5. It is strongly activated by Co2+ and inhibited by Fe2+, Cu2+, Ni2+, Zn2+, and ethylene diamine tetraacetic acid (EDTA). The specificity of the enzyme was investigated. Within several aminoacyl-p-nitroanilines (AA-pNA), Lys-pNA is proven to be the optimal substrate. The Michaelis-Menten constant (K-m) of the enzyme for Lys-pNA and Leu-pNA were 2.32 and 9.41mM, respectively. Peptide map fingerprinting shows that the sequence of the enzyme is highly similar to aminopeptidase Y from P. aeruginosa 18A. It can be speculated that this enzyme is a Zn2+-dependent enzyme and contains two zinc ions in its active site.

• 出版日期2014-10
• 单位江南大学