Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research, SAS Nagar, Punjab 160 062, India.
J Pharm Sci. 2010 Oct;99(10):4149-61. doi: 10.1002/jps.22129.
The aim of the study was to understand the effect of benzyl alcohol on biological activity, aggregation behavior, denaturant and heat-induced unfolding of lysozyme. Compatibility studies of lysozyme carried out with a number of anti-microbial preservatives, indicated benzyl alcohol to be the best suppressor of protein aggregation against heat stress. The effect of this preservative was checked at various pH values ranging from 4.0 to 9.0. In spite of reducing the thermal denaturation temperature (T(m)) at all pH values, benzyl alcohol had a stabilizing effect on lysozyme in terms of retaining the biological activity when the enzyme was incubated at 75 degrees C. The reduction in T(m) with increasing benzyl alcohol concentration was correlated with decreasing surface tension of surrounding medium. A detailed thermodynamic study of lysozyme in the presence of benzyl alcohol was carried out at pH 6.2. Change in Gibb's free energy of thermal unfolding at 25 degrees C was found to remain constant in the presence of benzyl alcohol, indicating no interaction of benzyl alcohol with the native protein at room temperature. Both the enthalpy and entropy change at mid point of thermal unfolding were found to increase in the presence of benzyl alcohol indicating the stabilization of partially unfolded state.
本研究旨在探讨苯甲醇对溶菌酶生物活性、聚集行为、变性剂和热诱导变性的影响。对溶菌酶与多种抗菌防腐剂的相容性研究表明，苯甲醇是抗热应激蛋白聚集的最佳抑制剂。该防腐剂的作用在 pH 值为 4.0 至 9.0 的不同范围内进行了检查。尽管在所有 pH 值下均降低了热变性温度 (T(m))，但苯甲醇在 75°C 孵育时对溶菌酶具有稳定作用，保留了生物活性。随着苯甲醇浓度的增加，T(m)的降低与周围介质表面张力的降低有关。在 pH 6.2 下，对苯甲醇存在下的溶菌酶进行了详细的热力学研究。在苯甲醇存在下，25°C 时热展开的吉布斯自由能变化保持不变，表明苯甲醇在室温下与天然蛋白质没有相互作用。在苯甲醇存在下，热展开中点的焓和熵变化均增加，表明部分展开状态的稳定性增加。
