Subtilisin (serine endopeptidase) is a non-specific protease (a protein-digesting enzyme) initially obtained from Bacillus subtilis.
Subtilisins belong to subtilases, a group of serine proteases that initiate the nucleophilic attack on the peptide (amide) bond through a serine residue at the active site. They are physically and chemically well-characterized enzymes. Subtilisins typically have molecular weights of about 20,000 to 45,000 dalton. They can be obtained from soil bacteria, for example, Bacillus amyloliquefaciens. Subtilisins are secreted in large amounts from many Bacillus species.
Subtilisin is an extracellular alkaline serine protease, it catalyzes the hydrolysis of proteins and peptide amides.