Figure 8.
Heme biosynthesis and fluorescence peak maxima according to the literature (Dietel et al., 2007; Seo et al., 2009; Lang et al., 2015). The porphyrinogen intermediates do not fluoresce, but they readily oxidize in situ, if oxygen is available, and form the delocalized system of π-electrons, which facilitates fluorescence. This process is further enhanced by irradiation.