ROLE OF THE 1ST AND 2ND COORDINATION SPHERE OF MANGANESE IN THE SOD AND CAT ACTIVITY

VERONICA DAIER; CLAUDIA PALOPOLI,; HERNAN BIAVA; DIEGO MORENO; MONICA DE GAUDIO; SANDRA SIGNORELLA,

BIOCELL

Lugar: Rosario; Año: 2009 vol. 33 p. 111 - 111

0327-9545

Catalases (CAT) and superoxide dismutases (SOD) deplete O2 •– and O2 = in cells through a ping-pong mechanism involving cyclic oxidation and reduction of the metal cofactor. To disproportionate O2 •–2 •– and O2 = in cells through a ping-pong mechanism involving cyclic oxidation and reduction of the metal cofactor. To disproportionate O2 •–and O2 = in cells through a ping-pong mechanism involving cyclic oxidation and reduction of the metal cofactor. To disproportionate O2 •–2 = in cells through a ping-pong mechanism involving cyclic oxidation and reduction of the metal cofactor. To disproportionate O2 •–in cells through a ping-pong mechanism involving cyclic oxidation and reduction of the metal cofactor. To disproportionate O2 •–2 •– and O2 = efficiently, the reduction potential of MnSOD and MnCAT is fine-tuned to values much lower than that of the Mn3+ (ac)/Mn2+ (ac)2 = efficiently, the reduction potential of MnSOD and MnCAT is fine-tuned to values much lower than that of the Mn3+ (ac)/Mn2+ (ac)efficiently, the reduction potential of MnSOD and MnCAT is fine-tuned to values much lower than that of the Mn3+ (ac)/Mn2+ (ac)3+ (ac)/Mn2+ (ac)/Mn2+ (ac) couple. In order to understand how the redox potential of Mn is modulated by its invironment, we have evaluated the redox potential and catalytic activity of two sets of water soluble mono- and dinuclear Mn complexes with the ligands: 1,3-bis(5-SO3- salicylidenamino)propan-2-ol, 1,3-bis(5-SO3-salicylidenamino) propane and 1,5-bis(5-SO3-3-X-salicylidenamino)pentan-3-ol (X = H, Cl o Me). The aromatic ring substituents were used to mimic secondary electrostatic/inductive effects of the protein while the donor sites in the chosen ligands mimic the Mn 1st coordination sphere. The redox potentials were determined by cyclic, linear and square-wave voltametry. The catalase activity was evaluated by measuring the oxygen concentration of H2O2 + catalyst mixtures with a Clark-type oxygen electrode. The SOD activity was assayed by measuring the inhibition of the photoreduction of nitro blue tetrazolium in the presence of the catalyst. Our results show that the 1st coordination sphere controls the potential of the redox couple and modulate the catalytic function, and that the redox potential vary linearly with the Hammett constant of the substituent.3- salicylidenamino)propan-2-ol, 1,3-bis(5-SO3-salicylidenamino) propane and 1,5-bis(5-SO3-3-X-salicylidenamino)pentan-3-ol (X = H, Cl o Me). The aromatic ring substituents were used to mimic secondary electrostatic/inductive effects of the protein while the donor sites in the chosen ligands mimic the Mn 1st coordination sphere. The redox potentials were determined by cyclic, linear and square-wave voltametry. The catalase activity was evaluated by measuring the oxygen concentration of H2O2 + catalyst mixtures with a Clark-type oxygen electrode. The SOD activity was assayed by measuring the inhibition of the photoreduction of nitro blue tetrazolium in the presence of the catalyst. Our results show that the 1st coordination sphere controls the potential of the redox couple and modulate the catalytic function, and that the redox potential vary linearly with the Hammett constant of the substituent.3-salicylidenamino) propane and 1,5-bis(5-SO3-3-X-salicylidenamino)pentan-3-ol (X = H, Cl o Me). The aromatic ring substituents were used to mimic secondary electrostatic/inductive effects of the protein while the donor sites in the chosen ligands mimic the Mn 1st coordination sphere. The redox potentials were determined by cyclic, linear and square-wave voltametry. The catalase activity was evaluated by measuring the oxygen concentration of H2O2 + catalyst mixtures with a Clark-type oxygen electrode. The SOD activity was assayed by measuring the inhibition of the photoreduction of nitro blue tetrazolium in the presence of the catalyst. Our results show that the 1st coordination sphere controls the potential of the redox couple and modulate the catalytic function, and that the redox potential vary linearly with the Hammett constant of the substituent.3-3-X-salicylidenamino)pentan-3-ol (X = H, Cl o Me). The aromatic ring substituents were used to mimic secondary electrostatic/inductive effects of the protein while the donor sites in the chosen ligands mimic the Mn 1st coordination sphere. The redox potentials were determined by cyclic, linear and square-wave voltametry. The catalase activity was evaluated by measuring the oxygen concentration of H2O2 + catalyst mixtures with a Clark-type oxygen electrode. The SOD activity was assayed by measuring the inhibition of the photoreduction of nitro blue tetrazolium in the presence of the catalyst. Our results show that the 1st coordination sphere controls the potential of the redox couple and modulate the catalytic function, and that the redox potential vary linearly with the Hammett constant of the substituent.st coordination sphere. The redox potentials were determined by cyclic, linear and square-wave voltametry. The catalase activity was evaluated by measuring the oxygen concentration of H2O2 + catalyst mixtures with a Clark-type oxygen electrode. The SOD activity was assayed by measuring the inhibition of the photoreduction of nitro blue tetrazolium in the presence of the catalyst. Our results show that the 1st coordination sphere controls the potential of the redox couple and modulate the catalytic function, and that the redox potential vary linearly with the Hammett constant of the substituent.2O2 + catalyst mixtures with a Clark-type oxygen electrode. The SOD activity was assayed by measuring the inhibition of the photoreduction of nitro blue tetrazolium in the presence of the catalyst. Our results show that the 1st coordination sphere controls the potential of the redox couple and modulate the catalytic function, and that the redox potential vary linearly with the Hammett constant of the substituent.st coordination sphere controls the potential of the redox couple and modulate the catalytic function, and that the redox potential vary linearly with the Hammett constant of the substituent.