Photosensitized production of nitric oxide and peroxynitrite from a carbon-bound diazenium diolate and 2-methyl-2-nitrosopropane

The photosensitized generation of nitric oxide from alanosine (3-(hydroxynitrosoamino)-d,l-alanine) by aluminum phthalocyanine tetrasulfonate (AlPcS4) is reported. While nitric oxide (NO) is obtained in nitrogen-saturated solutions, evidence suggest that both NO and peroxynitrite are produced in air-saturated solutions. Enhancement of NO production occurs in the presence of ubiquinone-0. These observations support the idea that NO is produced by the photosensitized oxidation of alanosine. Both NO and peroxynitrite are detected during photoirradiation of AlPcS4 in the presence of 2-methyl-2-nitrosopropane (MNP) and hypoxanthine (HX), but not in the absence of HX, in air-saturated solutions, thus implying that HX is acting as sacrificial electron donor, thus promoting superoxide formation.