Fig. 2
Enzyme activities of yCD and CNGRC-yCD proteins to transform 5-FC to 5-FU and the binding affinity of both proteins to the recombinant APN. a The recombinant APN protein was coated on a 96-well plate and then an increasing dose of protein solutions (0.0625, 0.125, 0.25, 0.5, 1.0, 2.0 and 4.0 μM) was added into the wells. The binding affinities of both yCD and CNGRC-yCD proteins to APN were determined by ELISA assay using horseradish peroxidase (HRP)–tagged anti-His6 antibody. b Increasing concentrations of 5-FC solutions (0.181, 0.363, 0.725, 1.5 and 3.0 mM) were added into a solution containing 50 nM of yCD or CNGRC-yCD fusion protein. The concentrations of 5-FC and 5-FU were determined by measuring the UV absorbance (λ255 and λ290) at 0.5, 1.0, 2.0 and 3.0 min after mixing 5-FC with the proteins. At least three repeats were performed with similar results