A sequence of 163 amino acids was derived from the nucleotide sequence of a DNA fragment bearing the colitis phage lytic enzyme gene. The molecular weight, basicity and the sequence of the three N-terminal amino acids agreed with those of the phage lytic enzyme. The amino acids at the N-terminal of the colitis phage enzyme are homologous with those of T4, P22 and phi 29 phage lysozymes, to the extent of 18-34%. The transcription initiation site was mapped at 166 nucleotides upstream to the translation initiation codon, ATG. The Shine-Dalgarno sequence, the Pribnow box and the RNA polymerase recognition site were at 5.10 and 35 nucleotdies respectively, upstream to the transcription initiation site. The transcription termination signal, (the inverted repeat) and the termination site (the oligo TS) were at 7 and 28 nucleotides respectively, downstream to the translation termination site, TAA.