Entner-Doudoroff glycolysis pathway as quadratic-cubic mixed autocatalytic network: A kinetic assay

Abstract

Concentration oscillations are ubiquitous phenomenon in biochemical systems.The present paper considers the simple nonlinear chemical feedback model for standard glycolytic route with prototype autocatalytic steps.Quadratic S + P ⇄ 2P.Cubic S + 2P ⇄ 3P.We couple these steps to get the mixed quadratic-cubic model but remarkable array of complex behavior and oscillatory patterns as expected on coupling is surprisingly missing. The observation is in conformity with natural glycolytic alternatives like the Entner-Doudoroff (ED), and phosphoketolase pathways found in Archaea – Thermoproteustenax and other prokaryotes. The fundamental and the practical implications of our findings are thoroughly discussed with pilot calculations and numerical simulations supported via non-linear dynamic analysis. A basic kinetic scheme is suggested for natural glycolytic alternative, ED pathway with its comparison and contrast to other standard routes for glucose metabolism. A key outcome of the study is the phenomenon of oscillator death for the coupled network. A discussion on the thermodynamic aspect of entropy production rate for the model networks are also presented for a comparison.