ON SPECIFICITY OF BACILLUS SUBTILIS NEUTRAL PROTEASE IN RELATION TO COMPOUND ACTIVE SITE

A previous paper indicated that a neutral protease of Bacillus subtilis has a large active site which can be divided into at least six subsites S1-S3 and S1′-S3′, on both sides of the catalytic site. Each subsite accomodates one amino acid residue of a peptide substrate, and is numbered S1, S2, etc. towards the NH2-end and S1′, S2′, etc. toward the COOH-end. To investigate the correlation between these six subsites and the specificity of the enzyme, kinetic studies were made using various synthetic peptides as substrates. The results led to the conclusion that the specificity is not always determined by all the subsites. The three subsites S1, S1′, and S2′ were the ones mainly concerned with the development of specificity, while the others were not always implicated. © 1969.