Pressure anomaly of the ATP hydrolysis rate facilitates life of extremophiles

Life is prevalent on Earth even in extreme environments, e.g., near black smokers. This biological community has to face temperatures of up to 120 °C and pressures of 40 MPa. To maintain vital reactions, extremophiles have developed varies mechanisms to survive. The stability of the energy-storing molecules adenosine triphosphate (ATP) and adenosine diphosphate (ADP) are of essential importance because reactions involving these phosphates constrain the range of life. ATP is limited by the non-enzymatic hydrolysis, which is kinetically enhanced at high temperatures. If this abiotic process is too rapid, metabolism as we know won’t be possible anymore. The effect of elevated temperatures on the hydrolysis rate constants of ATP is widely known and is best described by an Arrhenius relationship. In contrast to previous studies, our first findings showed a decelerating effect from 0 – 60 MPa with a minimum in the reaction rate at 20 – 40 MPa at 100 °C. The rate constants of the non-enzymatic hydrolysis of ATP are decreasing from 5.8 x 10-4 s-1 at 0.1 MPa to 4.2 x 10-4s-1 at 20 MPa at 100 °C. The corresponding half-lives are 1195 s and 20 MPa. This observation is extremely fascinating as Takai et al. (2008) have seen a similar pressure anomaly at extreme temperatures for Methanopyrus Kandleri.