Signaling and physiological activity of the NO-donating agent TNICthio in human blood lymphocytes, Jurkat and MCF7 cell lines.

Signaling and physiological activities of the crystalline tetranitrosyl iron complex with thiosulfate-a NO-donor (TNICthio) were first studied on human cells in conditions of mono and combined application of HS and antioxidants. Comparative studies were performed on three cell lines: normal and leukemic T lymphocytes (Jurkat cells) and breast cancer MCF-7 cells (human breast adenocarcinoma). Also established was a high biological activity of TNICthio, as well as correlation between the levels of reactive oxygen species generation, the formation of double-strand breaks (DSB) in DNA and cell proliferation.

Dinitrosyl iron complexes with glutathione as NO and NO⁺ donors.

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.

Electronic and spatial structures of water-soluble dinitrosyl iron complexes with thiol-containing ligands underlying their ability to act as nitric oxide and nitrosonium ion donors.

The ability of mononuclear dinitrosyl iron commplexes (M-DNICs) with thiolate ligands to act as NO donors and to trigger S-nitrosation of thiols can be explain only in the paradigm of the model of the [Fe(+)(NO(+))(2)] core ({Fe(NO)(2)}(7) according to the Enemark-Feltham classification). Similarly, the {(RS(-))(2)Fe(+)(NO(+))(2)}(+) structure describing the distribution of unpaired electron density in M-DNIC corresponds to the low-spin (S = 1/2) state with a d(7) electron configuration of the iron atom and predominant localization of the unpaired electron on MO(d(z2)) and the square planar structure of M-DNIC. On the other side, the formation of molecular orbitals of M-DNIC including orbitals of the iron atom, thiolate and nitrosyl ligands results in a transfer of electron density from sulfur atoms to the iron atom and nitrosyl ligands.

Autowave distribution of nitric oxide and its endogenous derivatives in biosystems strongly enhances their biological effects: A working hypothesis.

It is hypothesized that in cells producing nitric oxide (NO), NO and its endogenous derivatives (low-molecular S-nitrosothiols and dinitrosyl iron complexes (DNIC) with thiol-containing ligands) can move in the intracellular space not only by diffusion but also in an autowave mode. This hypothesis is based on the previously obtained data on autowave distribution of DNIC with glutathione following application of a drop of a solution of Fe(2+)+glutathione onto the surface of a thin layer of a S-nitrosoglutathione solution. The appearance of autowaves is conditioned by a self-regulating self-sustained system arising in the process.

Polynuclear water-soluble dinitrosyl iron complexes with cysteine or glutathione ligands: electron paramagnetic resonance and optical studies.

Electron paramagnetic resonance and optical spectrophotometric studies have demonstrated that low-molecular dinitrosyl iron complexes (DNICs) with cysteine or glutathione exist in aqueous solutions in the form of paramagnetic mononuclear (capital EM, Cyrillic-DNICs) and diamagnetic binuclear complexes (B-DNICs). The latter represent Roussin's red salt esters and can be prepared by treatment of aqueous solutions of Fe(2+) and thiols (small er, Cyrilliccapital EN, Cyrillic 7.4) with gaseous nitric oxide (NO) at the thiol:Fe(2+) ratio 1:1.