In order to estimate the rate determining step under photocatalytic conditions (Fig. ), we have calculated and compared the rates of MV 2+ reduction by organic NPs (υNRs-MV) with the rates of CODH reduction by reduced MV •+ (υMV-CODH). In all cases both for POZ-M(+) NRs and POZ-M (-) NRs, υNRs-MV are much higher (320 and 195 µmol•L -1 •h -1 ) than υMV-CODH (41 and 0.8 µmol•L -1 •h - 1 ), suggesting that the rate determining step of the photocatalysis is mainly the electron transfer from the redox mediator to CODH enzyme. From the steady-state fluorescence quenching experiment (Fig. ), one can see that 10 mM MV 2+ gives 75% oxidative quenching of POZ-M(+) NRs fluorescence, which is much more efficient than 16% reductive quenching given by 10 mM cysteine. It suggests that the excited POZ-M(+) NPs firstly reduce methyl viologen, and then the formed oxidized POZ-M NPs are regenerated by electron transfer from cysteine. Upon varying the concentration of cysteine (Fig. ), we observe little impact on the rate of MV 2+ reduction for POZ-M(+) NRs. Notably, upon addition of cysteine into POZ-M(-) NRs solution no quenching is observed, however the emission of POZ-M(-) NRs increases along with increase of cysteine concentration. This phenomenon shows a strong indication that the cysteine significantly changes the local chemical environment of POZ-M(-) NRs. Since we did not see significant change in absorption spectra of POZ-M(-) NRs in presence of cysteine (Fig. ), the POZ-M(-) NRs core packing should not be changed much. This phenomenon can also be observed in presence of MV 2+ at a concentration of more than 1 mM. We therefore hypothesize that the cysteine and MV 2+ must have a strong interaction with POZ-M(-) NRs, but it is challenging to conclude the quenching process/mechanism of POZ-M(-) NRs in presence of cysteine and MV 2+ . Nevertheless, the information obtained here is helpful for us to interpret the difference in photocatalytic performance between POZ-M(+) and POZ-M(-) NRs in presence of CODH enzyme, where limited electron transfer to enzyme is observed for POZ-M(-) NRs. Concurrently, generation of reduced MV 2+ by the negatively charged POZ-M(-) NRs is highly dependent on the concentration of cysteine (Fig. ). As mentioned in gel electrophoresis data and Cryo-EM (Fig. ), positively and negatively charged POZ-M NRs have different interaction with CODH enzyme. Armstrong et al. earlier highlighted that the photocatalytic activity of biohybrid assemblies was highly susceptible to the surface characteristics and shape of light harvesters that affected the co-attachment of the enzyme and the efficiency of electron transfer. To begin with POZ-M (+) NRs showed more efficient deactivation of the excited state via the electron transfer to redox mediator (Fig. ), in contrast to as prepared POZ-M NPs with hollow morphology (Fig. ). Furthermore, more efficient regeneration of POZ-M(+) NRs than in POZ-M(-) NRs under the same concentration of sacrificial electron donor, allowed to reach the regeneration plateau even with 10 mM cysteine (Fig. ). At the same time, even though negatively charged NRs are indeed able to give electrons to positively charged MV 2+ (Fig. ), the generated reduced MV •+ most likely gets trapped within surfactant chains of POZ-M(-) NRs and does not reach the enzyme units that are located further away (Fig. ). Thus, the relatively superior photocatalytic activity of positively charged NRs must be driven by more favourable surface morphology that reduce MV 2+ efficiently and have intimate interaction with CODH enzyme units, which allow the reduced MV 2+ to facilely reach the CODH enzyme, therefore resulting in efficient charge transfer.