Isolation and characterization of a staphylococcal enzyme bacteriolytic on streptococci

Staphylococcus hyicus, strain CCM 2368, produced a bacteriolytic enzyme, highly effective on streptococci, some staphylococci and micrococci. Production of the enzyme increased significantly following addition of NaCl (at 1.5%) to the growth medium. The bacteriolytic enzyme could be precipitated from the cell-free staphylococcal culture supernatant with ammonium sulfate at 60% saturation and partially purified by DEAE chromatography. Subsequent isoelectric focusing resulted in complete removal of proteolytic activity and revealed 2 bacteriolytic fractions. One of these (LE IIIa) had an isoelectric point near pH 9.8, the other (LE IIIb) near pH 10.3. LE IIIa lyzed more effectively streptococcal and LE IIIb micrococcal test cells. HPLC gel permeation chromatography also yielded 2 bacteriolytic fractions. The isolated staphylococcal enzyme appeared to be suitable for lysis of streptococci and solubilization of their cell wall structures.