Frequency-domain Enzyme Kinetics in the Context of Artificial Calcium Oscillations

The physiological function of intracellular calcium oscillations has eluded investigators. Given that calcium plays an important role in many signal transduction processes and that the frequency of oscillations can be controlled by external agonists, the biorhythmic phenomena may represent a type of frequencyencoded information train. In this thesis, I propose that calcium-activated, enzyme systems may act as a biomolecular "decoder" of these calcium signals. First, computer models were employed to demonstrate that a frequencyencoding/decoding paradigm is feasible at physiologically-relevant conditions. Then, several hardware/firmware implementations were constructed to generate artificial, calcium oscillations for in vitro study. Next, experiments were conducted with three calcium-activated, enzyme systems: phospholipase A-, calpain, and calcineurin. Finally, analytical software was developed to scrutinize empirical results for frequency-dependency and to account for variability in the artificially-generated, calcium oscillations. Thesis Supervisors: Professor Martha Gray Research Supervisor: Professor Joseph Bonventre