Abstract:Salmonella is common food-borne pathogen which could endanger public safety. Endolysin and holin, as new type of biological antibacterial agent, are functional proteins encoded by phages which can lyse bacteria. In this study, deca oligonucleotide primers and PCR technology were used to preliminarily identify phage SM-p2 and were used to determine genes of Hol 2 and Lys 2. Bioinformatics was used to predict the structural and physiological properties of these two proteins. E. coli expression system was used to express Lys 2 and Hol 2. The results showed that the bacteriophage SM-p2 was a dsDNA virulent bacteriophage with a ′holin-endolysin′ lysis system. Bioinformatics analysis showed that Hol 2 was a type III holin with only one transmembrane structure and Lys 2 was a peptidoglycan hydrolase without transmembrane structure. Both Lys 2 and Hol 2 could be successfully expressed by the E. coli expression system, but holins could directly disrupt bacterial inner membrane and had a toxic effect on competent expressing cells, resulting in less expression of Hol 2 in E. coli BL21 (DE3). Finally, Lys 2 and Hol 2 were obtained at the concentration of 5.419 mg/mL and 2.191 mg/mL, respectively. In this study, the gene of endolysin and holin of Salmonella phage SM-p2 were identified and successfully expressed, which laid a molecular foundation for antibacterial research of SM-p2.