Temperature Limit for the Emergence of Life-like System Deduced from the Prebiotic Chemical Kinetics under the Hydrothermal Conditions

The RNA world hypothesis and the hydrothermal origin of life hypothesis are contradictory to maintain life-like systems for these two hypotheses to be compatible by the following two main reasons. First RNA molecules are too labile and second the biologically important interactions would not be effective at high temperatures. The assumption can be applied to the protein-based life-like systems. We have continuously investigated the stability and the chemical evolution of RNAand protein-based life-like systems by using our hydrothermalmonitoring techniques. According to these data, it has been found that two viewpoints are essential to discuss the temperature limit of RNA and/or protein-based life-like systems on the primitive earth. First, the accumulation of biomolecules should be determined by both the formation and degradation rates. Second, the reaction rates of the primitive life-like systems should be evaluated from the viewpoint of enzymatic reaction rates.