In the ZnS settings, photosynthetically produced polycarbonic compounds,
inorganic polyphosphates, RNA-like oligomers, and diverse low-molecular-weight
phosphorylated derivates could serve as cleavage substrates for the first synthases.
The reducing equivalents that would be needed for some synthetic reactions were
continuously generated at the illuminated ZnS surfaces; nucleotide-containing
redox cofactors, such as NADH, NADPH, FAD, and FMN [22,214-216], could
have emerged as mediators that picked up the photoexcited electrons from photoactive
ZnS surfaces and delivered them to the respective ribozymes.