Marín Dolores, Sabater Bartolomé
Department of Physical Chemistry, University of Alcalá, Alcalá de Henares, 28805 Madrid, Spain.
Phys Biol. 2017 Apr 28;14(2):024001. doi: 10.1088/1478-3975/aa64a7.
Cancer cells consume more glucose by glycolytic fermentation to lactate than by respiration, a characteristic known as the Warburg effect. In contrast with the 36 moles of ATP produced by respiration, fermentation produces two moles of ATP per mole of glucose consumed, which poses a puzzle with regard to the function of the Warburg effect. The production of free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) per mole linearly varies with the fraction (x) of glucose consumed by fermentation that is frequently estimated around 0.9. Hence, calculation shows that, in respect to pure respiration, the predominant fermentative metabolism decreases around 10% the production of entropy per mole of glucose consumed in cancer cells. We hypothesize that increased fermentation could allow cancer cells to accomplish the Prigogine theorem of the trend to minimize the rate of production of entropy. According to the theorem, open cellular systems near the steady state could evolve to minimize the rates of entropy production that may be reached by modified replicating cells producing entropy at a low rate. Remarkably, at CO concentrations above 930 ppm, glucose respiration produces less entropy than fermentation, which suggests experimental tests to validate the hypothesis of minimization of the rate of entropy production through the Warburg effect.
癌细胞通过糖酵解发酵产生乳酸消耗的葡萄糖比通过呼吸作用消耗的更多,这一特征被称为瓦伯格效应。与呼吸作用产生36摩尔ATP相比,发酵每消耗1摩尔葡萄糖产生两摩尔ATP,这就瓦伯格效应的功能而言是一个谜题。每摩尔的自由能(ΔG)、焓(ΔH)和熵(ΔS)的产生与发酵消耗的葡萄糖比例(x)呈线性变化,该比例通常估计约为0.9。因此,计算表明,相对于纯呼吸作用,主要的发酵代谢使癌细胞中每消耗1摩尔葡萄糖的熵产生降低了约10%。我们假设增加发酵可能使癌细胞能够实现普里戈金定理中关于熵产生速率最小化的趋势。根据该定理,接近稳态的开放细胞系统可以进化以最小化熵产生速率,这可能通过以低速率产生熵的修饰复制细胞来实现。值得注意的是,在二氧化碳浓度高于930 ppm时,葡萄糖呼吸产生的熵比发酵产生的少,这表明需要进行实验测试来验证通过瓦伯格效应使熵产生速率最小化的假设。