Figure 3.

Photoactivation of a flavin-dependent photodecarboxylase. (a) Fluorescence titration results for the PtOEP:DPA@PS nanoparticle suspension (milli-Q water) recorded with increasing the concentration of a flavin-dependent photodecarboxylase (i.e., CvFAP) (0–42 μM). The huge peak marked with an asterisk is the excitation beam (550 nm). See SI, Figure S11 for the titration results for free FAD. (b) Lehrer plot which depicts the corrected fluorescence intensity of the upconverted emission of the PtOEP:DPA@PS nanoparticle suspension (i.e., I₀/(I₀ − I), where I₀ and I are the integrated values of the upconverted fluorescence intensities in the absence and presence, respectively, of CvFAP or FAD) as functions of 1/[CvFAP] and 1/[FAD], where [CvFAP] and [FAD] are molar concentrations of CvFAP and FAD, respectively.