Understanding in vivo regulation of photoautotrophic metabolism is important for identifying
strategies to improve photosynthetic efficiency or re-route carbon fluxes to desirable end products.
We have developed an approach to reconstruct comprehensive flux maps of photoautotrophic
metabolism by computational analysis of dynamic isotope labeling measurements and have applied
it to determine metabolic pathway fluxes in the cyanobacterium Synechocystis sp. PCC6803. Comparison to a theoretically predicted flux map revealed inefficiencies in photosynthesis due to oxidative
pentose phosphate pathway and malic enzyme activity, despite negligible photorespiration. This
approach has potential to fill important gaps in our understanding of how carbon and energy flows
are systemically regulated in cyanobacteria, plants, and algae