KINETIC-ANALYSIS OF HYDROTHERMAL REACTION S BY FLOW TUBE REACTOR - HYDROLYSIS OF ADENOSINE 5'-TRIPHOSPHATE AT 398-573K

A new method has been developed for kinetic analysis of hydrothermal r eactions to investigate chemical evolution of ribonucleic acid. The ap paratus consists of a high pressure pump, a sample loop injector, a hy drothermal Bow tube reactor, a cooling and back-pressure coil, and a s ampling port and the samples are pumped to the hydrothermal tube react or at constant Bow rate for heating. Pressure in the hydrothermal Bow tube reactor was regulated over the vapor pressure of water to keep th e sample solution as liquid using an appropriate length of back-pressu re coil. It was possible to monitor the consecutive hydrolysis of aden osine 5'-triphosphate (ATP) to hypoxanthine in the time rang of 0.4-14 0 a at 398-573 K and the rate constants for each step were determined by the computer program SIMFIT. Poly (tetrafluorothylene) (PTFE) and s tainless steel (SUS316) tubing have been examined for the hydrothermal flow tube reactor in which the apparent rate constants of ATP hydroly sis were in good agreement. The half life determined by the method was 0.31 a at 473 K for ATP and 0.42 s at 573 K for adenosine. This metho d enables real-time monitoring of model reactions of chemical evolutio n of RNA in aqueous solution at high temperatures.