Galina Nikolaevna Novodarova

Transition-metal complexes as catalysts of active oxygen species formation in autooxidation reactions: 2. Oxidative degradation of nucleic acids by cobalt and iron phthalocyanine complexes

Co- and Fe-phthalocyanine complexes with cationic and anionic substituents in the macroligand, which are effective in autooxidation of ascorbic acid in aqueous solutions, are studied in the reaction of oxidative cleavage of nucleic acids. It was shown for the first time that water-soluble, metal -phthalocyanine complexes can cleave nucleic acids in the reaction of dark conjugated autooxidation of ascorbic acid. Fe-octakis(pyridiniomethyl)phthalocyanine chloride is the most efficient in oxidative degradation of RNA target, and Co- and Fe-phthalocyanine cationic complexes are the most efficient in oxidative degradation of DNAs. Using the radical traps, it was shown that the oxidative degradation of nucleic acids is caused by OH-radicals.

Inhibition of catalytic autoxidation of dihydronicotinamide-adenine dinucleotide (NAD-H) by reaction products

1. The autoxidation of NAD-H in the presence of the Co(II) complex with 1,2,3,7,8,12,13,17,18,19-decamethyloctadehydrocorrin proceeds with the formation of H2O2, which leads to deactivation of the catalyst. 2. The addition of small amounts of the enzyme catalase leads to decomposition of the H2O2, and in this way facilitates a retention of the catalytic activity of the cobalt(II) complex. The Ni(II) complex with monoethanolamine exerts a similar effect.