Chen Nelson G, Gregory Kalvin, Sun Ye, Golovlev Val
Sci-Tec, Knoxville, TN, USA.
Biochim Biophys Acta. 2011 Oct;1814(10):1318-24. doi: 10.1016/j.bbapap.2011.06.010. Epub 2011 Jul 1.
The kinetics of enzyme deactivation provide useful insights on processes that determine the level of biological function of any enzyme. Photinus pyralis (firefly) luciferase is a convenient enzyme system for studying mechanisms and kinetics of enzyme deactivation, refolding, and denaturation caused by various external factors, physical or chemical by nature. In this report we present a study of luciferase deactivation caused by increased temperature (i.e., thermal deactivation). We found that deactivation occurs through a reversible intermediate state and can be described by a Transient model that includes active and reversibly inactive states. The model can be used as a general framework for analysis of complex, multiexponential transient kinetics that can be observed for some enzymes by reaction progression assays. In this study the Transient model has been used to develop an analytical model for studying a time course of luciferase deactivation. The model might be applicable toward enzymes in general and can be used to determine if the enzyme exposed to external factors, physical or chemical by nature, undergoes structural transformation consistent with thermal mechanisms of deactivation.
酶失活的动力学为确定任何酶的生物学功能水平的过程提供了有用的见解。萤火虫荧光素酶是一种方便的酶系统，用于研究由各种外部因素（本质上是物理或化学因素）引起的酶失活、重折叠和变性的机制及动力学。在本报告中，我们展示了一项关于温度升高导致荧光素酶失活（即热失活）的研究。我们发现失活通过一个可逆的中间状态发生，并且可以用一个包含活性和可逆非活性状态的瞬态模型来描述。该模型可作为分析复杂的多指数瞬态动力学的通用框架，这种动力学可通过反应进程测定法在某些酶中观察到。在本研究中，瞬态模型已被用于开发一个用于研究荧光素酶失活时间进程的分析模型。该模型可能普遍适用于酶，并且可用于确定暴露于外部因素（本质上是物理或化学因素）的酶是否经历了与热失活机制一致的结构转变。
