A moderately halophilic bacterium LY6 with high proteolytic activity was isolated. Biochemical and physiological characterization, along with 16S rDNA sequence analysis placed the isolate in the genus Halobacillus. The salinity of the culture medium strongly influenced the proteinase production of LY6. Maximum enzyme production was observed in the medium containing 5% Na(2)SO(4) or 10% NaCl. Proteinase production was synchronized with bacterial growth and reached a maximum level during the mid-stationary phase. Enzyme purification was carried out by a simple approach including a combination of ammonium sulfate precipitation and Sephacryl S-100 gel filtration chromatography. SDS-PAGE and gelatin zymography analysis revealed it was a monomer with high molecular weight of 69 kDa. Optimal proteinase activity was obtained at pH 10.0, 40°C, and 10% NaCl. It was high active over broad temperature (30-80°C), pH (6.0-12.0), and NaCl concentration (0-25%) ranges, indicating its thermostable, alkali-stable, and halotolerant nature. Moreover, the enzyme activity was markedly enhanced by Ca(2+) and Cu(2+), but strongly inhibited by EDTA, PAO, and DEPC, indicating that it probably was a metalloproteinase with cysteine and histidine residues located in its active site.
- MeSH
- chlorid sodný metabolismus MeSH
- fylogeneze MeSH
- Halobacillus klasifikace enzymologie genetika MeSH
- kationty dvojmocné MeSH
- koncentrace vodíkových iontů MeSH
- kultivační média chemie MeSH
- matrixové metaloproteinasy biosyntéza izolace a purifikace metabolismus MeSH
- molekulová hmotnost MeSH
- RNA ribozomální 16S genetika MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
