Reactions were screened using the F76A variant, both with and without the PEP/PK recycling system present (Figure ). A 2-fold excess of PEP was added to ensure efficient inhibition of TIM throughout the reaction while still enabling recycling of ATP. Addition of the PEP/PK recycling system resulted in an increase in conversion for all substrates screened, more closely matching conversions seen for the L cascade. In addition to the increase in conversion to product, the amount of DHAP side product also decreased (supplementary 10.4).