Non-enzymatic Hydrolysis of Adenosine Phosphates

Abstract

ENERGY transfer in living systems usually involves reactions in which adenosine triphosphate (ATP) is converted to adenosine di (ADP) or monophosphate (AMP) and inorganic phosphate. Similar reactions were probably necessary to provide energy for prebiological evolution. Concentrations of these compounds are affected by non-metabolic destruction, principally hydrolysis releasing orthophosphate. Thus the rates of such hydrolysis are of interest with respect both to present living systems and to the origin of life. Hydrolysis of ATP and ADP has been studied previously at selected temperatures and pH, both in distilled water and in the presence of several inorganic ions which might act as catalysts^1,2. The present work is concerned with reactions of ATP, ADP and AMP over a range of temperatures in distilled water, in 0.02 moles Ca²⁺ (previously reported to act as a catalyst), and in a synthetic seawater containing present oceanic concentrations of Na⁺, K⁺, Ca²⁺, Mg²⁺, Sr²⁺, Cl⁻, SO₄, HCO₃⁻, Br⁻ and H₂BO₃⁻. The latter medium was chosen as being as reasonable a representation as possible of primitive seawater, because the composition of the primitive seas, though not exactly known, was probably not drastically different from that of the present ones³.