Oxygen consumption in the marine bacterium Pseudomonas nautica predicted from ETS activity and bisubstrate enzyme kinetics
Oxygen consumption in the marine bacterium Pseudomonas nautica predicted from ETS activity and bisubstrate enzyme kinetics
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根据 ETS 活性和双底物酶动力学预测海洋细菌 Pseudomonas nautica 的耗氧量
DOI：
10.1093/plankt/18.10.1819
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发表时间：
1996
影响因子：
2.1
通讯作者：
J.
中科院分区：
文献类型：
--
作者：
T. Packard;E. Berdalet;D. Blasco;Sylvie O. Roy;L. St;B. Lagacé;K. Lee;J.
从呼吸电子转移系统(ETS)的体外活性、细菌蛋白质和培养物中碳源浓度的时间分布来模拟好氧细菌培养物中的呼吸耗氧量。该模型基于ETS在整个培养的指数、稳定和衰老阶段的双底物动力学控制的概念。在指数期，测定的耗氧率和体外ETS活性是紧密耦合的，而在衰老期，二者是非耦合的。体外ETS活性在碳源耗尽后仍保持较高水平，而耗氧量降至较低水平。基于这种解偶联是由胞内ETS底物(NADH和NADPH)的限制引起的假设，建立了一个结合双底物酶动力学算法的半经验模型，并与实验观察结果相吻合。该模型使用生理上真实的米氏常数和解离常数预测了培养过程中不同阶段的耗氧率，r2>；0.92(n=9，P<；0.001)。这些结果表明，通过测量浮游生物细胞内ETS底物(NADH和NADPH)以及浮游生物中的ETS活性，可以比以前更准确地评估野外浮游生物的呼吸。
The respiratory O2 consumption in aerobic bacterial cultures has been modeled from the time profiles of the in vitro activity of the respiratory electron transfer system (ETS), the bacterial protein and the concentration of the carbon source in the cultures. The model was based on the concept of bisubstrate kinetic control of the ETS throughout the exponential, steady-state and senescent phases of the cultures. In the exponential phase, the measured rates of O2 consumption and the in vitro ETS activity were closely coupled, but in the senescent phase, they were uncoupled. The in vitro ETS activity remained high even after the culture's carbon source was exhausted, while the O2 consumption fell to low levels. Based on the hypothesis that this uncoupling was caused by limitation of the intracellular ETS substrates (NADH and NADPH), a semi-empirical model incorporating a bisubstrate enzyme kinetics algorithm was formulated and fitted to the observations of the experiments. The model predicted the rate of O2 consumption throughout the different phases of the cultures with an r 2 > 0.92 (n = 9, P < 0.001) using physiologically realistic Michaelis and dissociation constants. These results suggest that plankton respiration in the field could be assessed more accurately than before by measuring the intracellular ETS substrates (NADH and NADPH), in addition to ETS activity, in plankton.
DOI：
10.1016/s0021-9258(17)42750-5
发表时间：
1984-08
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
K. Walsh;D. Koshland
通讯作者：
K. Walsh;D. Koshland