Abstract

Two-quantum photoreactions taking place under picosecond laser UV irradiation of DNA and RNA biopolymers were investigated. Despite of qualitative difference in two-step photoprocesses concerned (single-strand breaks formation in plasmid pBR 322 DNA, induction of breaks in TMV RNA sugar-phosphate chain, cross-links formation in DNA of CD phage) similar dependences of the quantum yield of the effects studied on the irradiation intensity can be observed with saturation in the region of 3 · 1011−3 · 1012 W/m2. The saturation intensity is one or two orders lower than in the case of irradiation of single monomers - nucleic acid bases.