Towards a comprehensive understanding of cellular metabolism
Abstract
Metabolism is the best mapped major biochemical network. Nevertheless, even in model organisms like baker’s yeast, important pathways continue to be discovered. One strategy for pathway discovery is to analyze, by untargeted LC-MS, the metabolic consequences of knocking out genes of unknown function. This approach recently identified a new route of converting glycolytic intermediates into ribose, which yeast cells activate when demand for ribose exceeds that for NADPH. With the aim of further elucidating pathways involving ribose and NADPH metabolism, we are now investigating several other poorly annotated enzymes. Multiple enzymes contribute to a ribose salvage pathway, which catabolizes ribosomal RNA to generate energy during nutrient starvation. Others contribute to NADPH homeostasis. The functional roles of these enzymes and pathways in the context of energy and cofactor metabolism will be described.