Characterization of a new oxidant-stable serine protease isolated by functional metagenomics.

ABSTRACT: A novel serine protease gene, SBcas3.3, was identified by functional screening of a forest-soil metagenomic library on agar plates supplemented with AZCL-casein. Overproduction in Escherichia coli revealed that the enzyme is produced as a 770-amino-acid precursor which is processed to a mature protease of ~55 kDa. The latter was purified by affinity chromatography for characterization with the azocasein substrate. The enzyme proved to be an alkaline protease showing maximal activity between pH 9 and 10 and at 50°C. Treatment with the chelating agent ethylenediaminetetraacetic acid irreversibly denatured the protease, whose stability was found to depend strictly on calcium ions. The enzyme appeared relatively resistant to denaturing and reducing agents, and its activity was enhanced in the

SUBMITTER: Biver S 

PROVIDER: S-EPMC3765597 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature