Graduate Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02254-9110.
alpha-Lytic protease is a 19.8-kDa protein secreted from the Gram-negative bacterium Lysobacter enzymogenes. We have cloned and sequenced the gene for this serine protease. The nucleotide sequence contains an open reading frame which codes for the 198-residue mature enzyme and a potential prepro-peptide, also of 198 residues. The COOH-terminal 49 residues of the pro-peptide are significantly homologous to the propeptides of Streptomyces griseus proteases A and B. We suggest that this pro-peptide region facilitates formation of the active enzyme. A region bridging the NH2-terminal pre- and pro-peptides is homologous to a maize inhibitor of serine proteases. We speculate that this region inhibits enzymatic activity of the prepro-enzyme.