Antifungal and antibacterial functions of medicinal leech recombinant destabilase-lysozyme and its heated-up derivative

Antifungal activity of recombinant medicinal leech destabilase-lysozyme (rec.Dest-Lys) was investigated by using fungi: Botrytis cinerea, and Verticillium lateriticum, including yeasts Candida guillermoudii and Shizosaccharomyces pombe. Its antibacterial activity was investigated on gram-negative bacteria Pseudomonas fluorescens. These activities were assessed by radial agar diffusion assay, and scanning and transmission electron microscopy. Therefore, destabilase-lysozyme not only is endo-isopeptidase and lysozyme, but also has antifungal and antibacterial activities. Muramidase activity of rec. Dest-Lys disappeared after heat-treating at 90°C for 50 min without the loss of its antimicrobial activity. Furthermore we showed for the first time that the heated-up derivative of rec.Dest-Lys exhibited more potent activities against the above enumerated fungi and gram-negative bacteria than original protein.