Bioenergetics: Open Access

Abstract

Still at the Center of it All; Novel Functions of the Oxidative Krebs Cycle

Ryan J. Mailloux

The Krebs cycle is a universal metabolic cascade furnishing all organisms on Earth with the basic building blocks of life. Flux through the Krebs cycle is required to drive the production of the universal energy currency ATP. Carbon intermediates from the Krebs cycle also serve as precursors for the genesis of amino acids, lipids, and nucleotides. Considering that carbon in the Krebs cycle generates all the requisite ingredients that allow life to flourish it is easy to reconcile why it is found in all organisms. Although we have an eloquent understanding of the Krebs cycle and its function in relation to biochemistry and physiology, the basic tenets of this pathway are still being studied. This can be attributed to discoveries showing the Krebs cycle fulfills various other cellular functions including antioxidant defense, control of transcription, and cellular signaling. In the present article, I will discuss the novel functions of the Krebs cycle including its role in antioxidant defense, reactive oxygen species (ROS) production, and signaling. These functions are inherently related to its central function, carbon metabolism and mobilization of electrons for energy production or anabolic reactions. These novel Krebs cycle functions are influenced by the efficiency of nutrient metabolism and electron transfer reactions, two factors that are fundamental to the existence of life on Earth.