Study of chemical structure and of photochemical activity of abiogenic flavin pigment

A product with molecular mass of 500-550 Da was isolated from a pigmented material formed by thermolysis (185degreesC) of a mixture of glutamic acid, glycine, and lysine (the optimal molar ratio of 8: 3: 1). After purification by chromatography the spectra of absorption and luminescence as well as IR- and PMR-spectra of the isolated pigment were studied. Based on the obtained data, the pigment was identified as a structural analogue of biological flavins: isoalloxazine heterocycle with two hydroxyl groups as well as a substitute of the amino acid nature. Like natural flavins, the abiogenic pigment photosensitized in solution both anaerobic and aerobic reactions of electron transfer from donors (ascorbate, Na-2-EDTA) to acceptors (redox-sensitive dyes, nicotinamide, Mo(IV)), with the rate practically identical to that in the case of use of riboflavin. The ability of abiogenic flavin and riboflavin to photosensitize redox reactions was preserved after absorption or their molecules on particles or clay minerals (kaolinite, bentonite, celite); however, the absorption affected the rate of individual photochemical reactions.