A staphylolytic fusion protein (chimeric enzyme K-L) was created, harboring three unique lytic activities composed of the LysK CHAP endopeptidase, and amidase domains, and the lysostaphin glycyl-glycine endopeptidase domain. To assess the potential of possible therapeutic applications, the kinetic behavior of chimeric enzyme K-L was investigated. As a protein antimicrobial, with potential antigenic properties, the biophysical effect of including chimeric enzyme K-L in anionic polymer matrices that might help reduce the immunogenicity of the enzyme was tested. Chimeric enzyme K-L reveals a high lytic activity under the following optimal ((opt)) conditions: pH(opt) 6.0-10.0, t(opt) 20-30 A degrees C, NaClopt 400-800 mM. At the working temperature of 37 A degrees C, chimeric enzyme K-L is inactivated by a monomolecular mechanism and possesses a high half-inactivation time of 12.7 A +/- 3.0 h. At storage temperatures of 22 and 4 A degrees C, a complex mechanism (combination of monomolecular and bimolecular mechanisms) is involved in the chimeric enzyme K-L inactivation. The optimal storage conditions under which the enzyme retains 100 % activity after 140 days of incubation (4 A degrees C, the enzyme concentration of 0.8 mg/mL, pH 6.0 or 7.5) were established. Chimeric enzyme K-L is included in complexes with block-copolymers of poly-l-glutamic acid and polyethylene glycol, while the enzyme activity and stability are retained, thus suggesting methods to improve the application of this fusion as an effective antimicrobial agent.