Two bacteriolytic enzymes secreted by Achromobacter lyticus M497-1 were purified and identified as being very similar (considering their amino acid composition and N-terminal sequence) to alpha- and beta-lytic proteases from Lysobacter enzymogenes. A 1.8-kb EcoRI fragment containing the structural gene for beta-lytic protease was cloned from A. lyticus chromosomal DNA. The protein sequence deduced from the nucleotide sequence was identical to the known sequence of beta-lytic protease, except for six residues. The nucleotide sequence revealed that the mature enzyme is composed of 179 amino acid residues with an additional 195 amino acids at the amino-terminal end of the enzyme, which includes the signal peptide, thus indicating that the enzyme is synthesized as a precursor protein.