Ultrasound-induced formation of S-nitrosoglutathione and S-nitrosocysteinein aerobic aqueous solutions of glutathione and cysteine

S-Nitrosocompounds are formed when aqueous solutions of cysteine or glutath ione are exposed to ultrasound (880 kHz) in air. The yield of the S-nitroso compounds was as high as 10% for glutathione and 4% for cysteine of the ini tial thiol concentrations (from 0.1 to 10 mM) in the aqueous solutions. In addition to the formation of S-nitrosocompounds, thiol oxidation to disulfi de forms was observed. After the oxidation of over 70% of the sulfhydryl gr oups, formation of peroxide compounds as well as cysteic acid derivatives w as recorded. The formation of the peroxide compounds and peroxide radicals in the ultrasound field reduced the yield of S-nitrosocompounds, S-Nitrosoc ompounds were not formed when exposing low-molecular-weight thiols to ultra sound in atmospheres of N-2 or CO. In neutral solutions, ultrasound-exposed cysteine or glutathione released NO due to spontaneous degradation of the S-nitrosocompounds. N2O3, produced due to the spontaneous degradation of th e S-nitrosocompounds in air, nitrosylated sulfhydryl groups of glutathione manifested in the appearance of new absorption bands at 330 and 540 nm. The nitrogen compounds formed in an ultrasound field modi fled the sulfhydryl groups of apohemoglobin and serum albumin. The main target for ultrasound-g enerated oxygen free radicals were cystine residues oxidized to cysteic aci d residues.