The influence of copper on alkaline protease stability toward autolysis and thermal inactivation
The influence of copper on alkaline protease stability toward autolysis and thermal inactivation
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DOI：
10.1002/elsc.201200017
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发表时间：
2012-11-01
影响因子：
2.7
通讯作者：
Erarslan, Altan
中科院分区：
文献类型：
--
作者：
Ozturk, Nurcin Celik;Kazan, Dilek;Erarslan, Altan
碱性蛋白酶是最重要的一类酶，在许多不同的工业部门中是不可缺少的。研究了不同温度（45-65 ℃）下铜离子（Cu 2+）对提高克劳氏芽孢杆菌GMBE 42碱性蛋白酶热稳定性和水解性能的影响。在5 mM CuCl 2存在下观察到最大残留活性。酶的热灭活符合一级动力学。由铜离子引起的稳定化效应是自溶和热灭活率降低的结果。热灭活过程的热力学分析表明，Ea，i，？吉，然后呢？Hi值的酶较高的铜离子的存在下，但没有可测量的变化？Si值。这些结果显示了铜离子对酶的热稳定潜力。较低的Km值和较高的kcat和kcat/Km值，得到在铜离子的存在下，这是一个指示的非必需的铜离子激活的酶。酪蛋白水解的热力学分析表明，在铜离子的存在下，Ea，？G？? H？? GE-S？然后呢？GE-T？酶的值降低，但没有变化？S吗？价值观这是迄今为止第一个研究阳离子对碱性丝氨酸蛋白酶的基本催化和热力学性质的影响的研究，该碱性丝氨酸蛋白酶可用于去除食品和皮革加工等各种行业的蛋白质废物。
Alkaline proteases are one of the most important group of enzymes that are indispensable in a number of different industrial sectors. In this work, the effect of copper ions (Cu2+) was investigated for improving the thermostability and hydrolytic performance of Bacillus clausii GMBE 42 alkaline protease at different temperatures (45-65 degrees C). Maximal residual activity was observed in the presence of 5 mM CuCl2. The enzyme was thermoinactivated according to first-order kinetics. A stabilization effect caused by copper ions was the result of a decrease in both autolysis and thermoinactivation rates. Thermodynamic analysis of the thermoinactivation process showed that Ea,i, ?Gi, and ?Hi values of the enzyme were higher in the presence of copper ions, but there was no measurable change in ?Si values. These results show the thermostabilizing potential of copper ions on the enzyme. Lower Km values and higher kcat and kcat/Km values were obtained in the presence of copper ions, which is an indication of the nonessential activation of the enzyme by copper ions. Thermodynamic analysis of casein hydrolysis showed that in presence of copper ions Ea, ?G?, ?H?, ?GE-S?, and ?GE-T? values of enzyme were lower, but there was no change in ?S? values. This is so far the first study that investigates the effect of cations on the basic catalytic and thermodynamic properties of an alkaline serine protease, which may be used to remove protein wastes from various industries such as food and leather processing.