Parameter Optimization for Biochemical Reactions in Phototransduction
by
Vasilios Alexiades
Mathematics, University of Tennessee, Knoxville TN

Vision begins when photons are captured by rhodopsin molecules in photoreceptor cells in the back of the retina. Activation of rhodopsin instigates a cascade of biochemical reactions, which eventually results in reduction of the steady (dark) current across the photoreceptor membrane. This is the signal that propagates to the brain enabling us to see.

We study a model of the biochemical cascade with multi-stage shutoff of activated rhodopsin (described by 70 reactions involving 16 primary parameters). A sensitivity analysis suggests that 4 of the parameters affect the response the most. We present an approach to find parameters that result in desired peak and timing of the response matching experimental data.

Date received: March 21, 2007