Background

The mitochondrial electron transport chain (ETC) is a massive complex that enables the mitochondria to synthesize approximately 34 molecules of ATP per molecule of glucose. A number of mitochondrial disorders have been found to be due to defective ETC. Cell proliferation requires a functional ETC and interestingly, it has long been observed that cells lacking a functional ETC can proliferate in the presence of high concentrations of pyruvate. Scientists at Whitehead Institute and the Massachusetts Institute of Technology have determined that the only essential function of the electron transport chain in proliferating cells is to biosynthesize aspartate. This observation supports the notion that proliferating cells adjust their metabolism to support macromolecular biosynthesis at the expense of ATP synthesis.