新陳代謝反応を解析する試案 II

化学装置としてみた生体の減価償却とエントロピー代謝

抄録

Thermodynamical analysis of life is given in this report. Our body is analogous to fuel cell, which is the power source of isothermal change. ATP is the power transmitting medium corresponding to the current of fuel cell. The main part of the out put in fed back to the living system to maintain life. Life mag be the function of such feed back system. The balance of free energy in such system is analysed and the mathematical relation like that of simple reproduction in economics is obtained with applying the maximum principle of transient phenomena, for the system of living body and its environment is an instance of transient phenomena of chemical flow.
From the equation we can estimate the chemical potential of our body in living state, if we can measure the rates of biochemical reactions. The main part of the chemical potential is the term due to the negative entropy, which is being destructed thermodynamically and reconstructed. Some author is confined to apparent steadiness of the nagative entropy and inclined to the opinion that the destruction, which is the character of catabolism, is frozen or delayed during our life until death. Such consideration is absurd, if we take the metabolic turnover into consideration. The steadiness of negative entropy is maintained by the reconstruction. On the other hand the process, which is anabolism, seams to the reversed course from the point of thermodynamics. But in fact it does not contradict to the second low, if we take the total system of our body and environment into consideration. Such reversed course is the common feature of transient phenomena.
Schrödinger has suggested that we might eat the negative entropy. But it is not adeguats, for there is production of positive entropy due to catabolism and it is excreted (Entropieströmung). Therefore we must take negative entropy at toilet and vomit it at dining room from the point of thermodynamics of irreversible phenomena. But Echrödinger has at first suggested the metasolic turnover of entropy, though he might not be conscious of it. Negative entropy must be the measure of delicacy of living system as the chemical apparatus, which corresponds to the fixed assets and depreciates according to the analogy of economics. The value of negative entropy depreciates and repaired by anabolism. At may be reasonable to measure the value of negative entropy by observing the rate of production by the delicate apparatus.
There might be nothing in living system contradicting the law of physics and chemistry. New principle may be the maximum principle, if it is required, and the author proposed to call it the fourth law of thermodynamics.