An Application of Reverse Quasi Steady State Approximation over SERCA

Abstract

Many cell types encode signals in the frequency component of calcium oscillations. In non-excitable cells calcium oscillations are induced by calcium influx from inositol trisphosphate receptors (IP3R) or/and ryanodine receptors (RyR). The frequency of Calcium oscillations induced in such cases is primarily by the way intracellular stores like endoplasmic reticulum, sarco-endoplasmic reticulum are refilled. Sarco-endoplasmic reticulum calcium ATPase (SERCA) is the major pathway by which this refilling process is effected. Most of the mathematical models proposed thus far used Michaelis-Menten kinetics to formulate SERCA pump. In this paper more emphasis has been given over the mathematical formulation of SERCA pump. In particular reverse quasi steady-state approximation (rQSSA) is used to formulate SERCA pump. Comprehensive comparative analysis is performed with the previous SERCA pump formulation. An apparent increase in frequency and amplitude of calcium oscillation is observed. Keywords - SERCA, Michelis-Menten, rQSSA, Enzyme Kinetics.