An experimental study is proposed on the thermodynamic efficiency of biochemical and biological energy transduction devices (pumps). The specific system proposed consists of the glycolytic reaction of fructose- 6-phosphate with ATP to produce fructose-diphosphate and ADP, the reaction being catalyzed by the enzyme phosphofructokinase. This reaction, in a vessel, is driven by the illumination of added chromatophores which regenerate ATP. The reverse reaction is catalyzed in a second vessel connected to the first by a membrane. The membrane is permeable to all chemical species except enzymes. Upon illumination of the first vessel a gradient in concentrations of FDP and F6P is established between the two vessels and this gradient can be related to the efficiency of the pumping process, which is the ratio of the power output divided by the power input. Measurements are planned on the efficiency for periodically varying light intensity at various frequencies and amplitudes compared to the efficiency with steady illumination. Prior theories predict the possibility of increasing the efficiency of such nonlinear pumps by means of external periodic variations of constraints such as the illumination, and the purpose of the measurements is to test these predictions. A second system is the proton pump in bacteriorhodopsin, either by itself or coupled to catalyzed by horseradish peroxidase (HPO). The HPO reaction is known to be oscillatory. An understanding of the thermodynamic efficiency of nonlinear energy transduction systems is important for the foundation of bioenergetics necessary for investigation of related diseases such as myopathies (genetic mitochondrial diseases).
