... during the course of prepar-ation cannot be excluded, but that still leaves unanswered the question of how the addition of micromolar concentra-tions of NADPH suffice to drive the conversion of ... nm rather than 640 nm, asillustrated in Fig. 2. Under these conditions, there isminimal photoconversion of the sample on exposure tolight. On addition of NADPH, however, the absorptionmaximum ... 12B. The effect of the presence of the adenylates on the ability of POR-PChlide640to undergophotoconversion was checked by comparing the efficiency of photoconversion of PLB samples containing...