Lysin 2638aR and chimeric Ply187AN-KSH3b fusion protein are capable of lysing antibiotic-resistant strains of Staphylococcus aureus and are promising alternatives to antibiotics. Studies on the stability and structure of lysins 2638aR and Ply187AN-KSH3b are important for assessing the feasibility of their practical use. Both lysins are highly active at physiological pH (7.5) and at low salt content (the concentration of NaCl in the reaction medium is not more than 250 mM). Lysins are inactivated by a monomolecular mechanism and have high stability at 4 °C (storage temperature). The maximum value of the half-inactivation time for lysin 2638aR is 190-200 days (500-1000 mM NaCl, pH 6.0-7.5), for lysin Ply187AN-KSH3b is 320-340 days (10-1000 mM NaCl, pH 6.0). The lysins are pretty stable in human blood serum (the half-inactivation time is 0.5-2 h) at 37 °C. The lysins undergo denaturation in large part due to the destruction of the α-helices at temperatures above 40 °C.

中文翻译：

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溶菌酶失活的动力学：定性和定量描述。

溶素2638aR和嵌合的Ply187AN-KSH3b融合蛋白能够裂解金黄色葡萄球菌的抗药性菌株，并有望替代抗生素。溶血素2638aR和Ply187AN-KSH3b的稳定性和结构的研究对于评估其实际应用的可行性非常重要。两种溶菌素在生理pH值（7.5）和低盐含量下（反应介质中的NaCl浓度不超过250 mM）都具有很高的活性。溶素通过单分子机理失活，并在4°C（储存温度）下具有很高的稳定性。溶素2638aR的半灭活时间的最大值是190-200天（500-1000 mM NaCl，pH 6.0-7.5），溶素Ply187AN-KSH3b的半灭活时间是320-340天（10-1000 mM NaCl，pH 6.0） 。溶血素在人血清中相当稳定（半灭活时间为0。5-2 h）在37°C下。由于在40°C以上的温度下α螺旋的破坏，溶菌素发生很大程度的变性。