Mitogenetic radiation (MGR), discovered by A. G. Gurwitsch, gave birth to the field of biophotonics that is now energetically developing. However, most facts of unique properties of MGR and of processes in which they originate, of the surprising discoveries made during several decades of intensive MGR research, are practically forgotten. Present-day biophotonics may gain a lot for its further development from discoveries and insights made at that time. In particular, it was discovered that usual enzymatic reactions are followed with MGR, that MGR emission from aqueous solutions of simple amino acids is correlated with spontaneous polypeptide synthesis, that substances possessing specific enzymatic activities may self-reproduce in such solutions. All these processes crucially depend on oxygen (and in some cases on illumination with visible light). An extremely sensitive analytical method -MGR spectral analysishelped to show that branched chain reactions with the participation of reactive oxygen species and other free radicals serve as energy sources for the emergence of high energy mitogenetic photons. All these amazing phenomena are discussed, in particular here in relation to the growing understanding of the important role of reactive oxygen species and their reactions taking place In aqueous milieu for bioenergetics and bioinforrnatics.