The use of cell-free enzymatic catalysis for carrying out biosynthesis reactions (e.g. synthesis of antibiotics, carbohydrates, prostaglandins) has great potential but is as yet virtually unexplored. In many such reactions adenosine triphosphate (ATP) serves as an important energy source where the terminal phosphate bonds of ATP are sacrificed to produce either adenosine diphosphate (ADP) or adenosine monophosphate (AMP). If biosynthetic reactions are ever to be realized on a large scale, economic regeneration of ATP from ADP or AMP will be necessary.

The regeneration can be accomplished through the utilization of two enzymatic reactions, those catalyzed by adenylate and acetate kinase in the presence of magnesium ions. In this study, complete conversion to ATP starting with either ADP or AMP has been accomplished. The equilibrium thermodynamics of the two kinase reactions have been studied experimentally and theoretically and a predictive model for ATP conversion has been confirmed. Acetate kinase has been stabilized for a period of months at 34°C by sequential addition of dithiothreitol (DTT). Its previously reported lifetime was several days. The kinetics of acetate kinase have been thoroughly examined. Desirable operating conditions with respect to pH, magnesium ions, substrates, products, and certain non-reactive species have been identified. A kinetic model has been developed and confirmed. Separation of ATP from the primary byproduct of the ATP regeneration reactions, acetate, has been demonstrated using a variety of techniques.