On the dynamics of the adenylate energy system: homeorhesis vs homeostasis.

摘要: Biochemical energy is the fundamental element that maintains both adequate turnover of biomolecular structures and functional metabolic viability unicellular organisms. The levels ATP, ADP AMP reflect roughly energetic status cell, a precise ratio relating them was proposed by Atkinson as adenylate charge (AEC). Under growth-phase conditions, cells maintain AEC within narrow physiological values, despite extremely large fluctuations in adenine nucleotides concentration. Intensive experimental studies have shown these values are preserved wide variety organisms, eukaryotes prokaryotes. Here, to understand some elements involved cellular status, we present computational model conformed key essential parts system. Specifically, considered (I) main synthesis process ATP from ADP, (II) catalyzed phosphotransfer reaction for interconversion AMP, (III) enzymatic hydrolysis yielding (IV) providing AMP. This leads dynamic (with form delayed differential system) which rate equations all kinetic parameters been explicitly experimentally tested vitro. Our central hypothesis characterized changing dynamics (homeorhesis). results show presents stable transitions between steady states periodic oscillations and, agreement with data range window. Furthermore, shows sustained Gibbs free total nucleotide pool. study provides step forward towards understanding principles quantitative laws governing system, unveiling life.