ИСТИНА

Bacteriophage lytic enzymes are promising agents for the treatment of diseases caused by antibiotic-resistant strains of Staphylococcus aureus. The staphylococcal phage phi11 endolysin (LysPhi11) can effectively lyse S. aureus cells, including strains resistant to methicillin and vancomycin. Enzyme structure and kinetic behavior have not previously been characterized. It is shown that at 37°C LysPhi11 loses activity due to thermal denaturation and aggregation of its molecules. Under optimal storage conditions (4°C, pH 6.0-8.0, 10 mM NaCl) LysPhi11 half-inactivation time is equal to 3-4 months. In the storage conditions the enzyme is inactivated by monomolecular mechanism; conformational changes in the molecule may be accompanied by disruption of the structure of Me++-binding site and transition of cysteine residues to the deprotonated form.