title: Dinitrosyl iron complexes with glutathione as NO and NO⁺ donors.
abstract: It has been found that heating of solutions of the binuclear form of dinitrosyl iron complexes (B-DNIC) with glutathione in a degassed Thunberg apparatus (рН 1.0, 70°С, 6 h) results in their decomposition with a concomitant release of four gaseous NO molecules per one B-DNIC. Further injection of air into the Thunberg apparatus initiates fast oxidation of NO to NO₂ and formation of two GS-NO molecules per one B-DNIC. Under similar conditions, the decomposition of B-DNIC solutions in the Thunberg apparatus in the presence of air is complete within 30-40 min and is accompanied by formation of four GS-NO molecules per one B-DNIC. It is suggested that the latter events are determined by oxidation of B-DNIC iron and concominant release of four nitrosonium ions (NO⁺) from each complex. Binding of NO⁺ to thiol groups of glutathione provokes GS-NO synthesis. At neutral рН, decomposition of B-DNIC is initiated by strong iron chelators, viz., о-phenanthroline and N-methyl-d-glucamine dithiocarbamate (MGD). In the former case, the reaction occurs under anaerobic conditions (degassed Thunberg apparatus) and is accompanied by a release of four NO molecules from B-DNIC. Under identical conditions, MGD-induced decomposition of B-DNIC gives two EPR-active mononuclear mononitrosyl iron complexes with MGD (MNIC-MGD) able to incorporate two iron molecules and two NO molecules from each B-DNIC. The other two NO molecules released from B-DNIC (most probably, in the form of nitrosonium ions) bind to thiol groups of MGD to give corresponding S-nitrosothiols. Acidification of test solutions to рН 1.0 initiates hydrolysis of MGD and, as a consequence, decomposition of MNIC-MGD and the S-nitrosated form of MGD; the gaseous phase contains four NO molecules (as calculated per each B-DNIC). The data obtained testify to the ability of B-DNIC with glutathione (and, probably, of B-DNIC with other thiol-containing ligands) to release both NO molecules and nitrosonium ions upon their decomposition. As far as nitrosyl iron complexes with non-thiol-containing ligands predominantly represented by the mononuclear mononitrosyl iron form (MNIC) are concerned, their decomposition yields exclusively NO molecules.
authors.affiliation: N.N. Semyonov Institute of Chemical Physics, Russian Academy of Sciences, Moscow, Russia.
authors.forename: Rostislav R
authors.initials: RR
authors.lastname: Borodulin
authors.forename: Lyudmila N
authors.initials: LN
authors.lastname: Kubrina
authors.forename: Vasak D
authors.initials: VD
authors.lastname: Mikoyan
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Poltorakov
authors.forename: Vyacheslav О
authors.initials: VО
authors.lastname: Shvydkiy
authors.forename: Dosymzhan Sh
authors.initials: DSh
authors.lastname: Burbaev
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Serezhenkov
authors.forename: Elena R
authors.initials: ER
authors.lastname: Yakhontova
authors.forename: Anatoly F
authors.initials: AF
authors.lastname: Vanin
mesh_terms: D005978:Glutathione / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D015394:Molecular Structure; D009569:Nitric Oxide / Q000737:chemistry*; D020030:Nitric Oxide Donors / Q000737:chemistry*; D009589:Nitrogen Oxides / Q000737:chemistry*; D010084:Oxidation-Reduction
chemical_list: D020030:Nitric Oxide Donors; D009589:Nitrogen Oxides; C504137:nitrosonium ion; D009569:Nitric Oxide; C073661:dinitrosyl iron complex; D007501:Iron; D005978:Glutathione