Characterization of an alkaline serine protease from an alkaline-resistant Pseudomonas sp.: Cloning and expression of the protease gene in Escherichia coli

Summary A gene, aprP, encoding an extracellular alkaline serine protease from a newly isolated Pseudomonas sp. KFCC 10818 was cloned and characterized. Nucleotide sequence analysis revealed an open reading frame of 1,266 nucleotides which could encode a polypeptide comprised of 422 amino acids. The C-terminal 283 residues showed an overall sequence homology with the subtilisin-type serine proteases. When expressed in E. coli, the alkaline protease, AprP, was released to the culture medium. The purified AprP was most active at pH 11. The k _Cat/K _m value of this enzyme was 9.2 × 10³ S^–1mM^–1, which is much higher than those of subtilisins.