These complexes exhibit significant catalytic activity towards the dismutation
of superoxide anions.
Catalase employs a two-electron transfer in the dismutation
of hydrogen peroxide ([H.sub.2][O.sub.2]) to oxygen gas and water, thereby protecting the cell from the harmful effects of [H.sub.2][O.sub.2].
The latter can undergo dismutation
to form hydrogen peroxide.
of aldehydes by a bacterial enzyme.
Because apo[E.sup.-/-], SOD[2.sub.+/-] mice generate highet levels of[O.sub.2.sup.-], the * NO/[O.sub.2.sup.-] ratio in these animals would be lower, shifting reaction of [O.sub.2.sup.-] toward [H.sub.2][O.sub.2] production via spontaneous or enzymatically mediated dismutation
of [O.sub.2.sup.-] Additionally, [SOD2.sup.+/-] mice have significantly decreased levels of reduced glutathione (Van Remmen et al.
The spontaneous or catalyzed dismutation
of [O.sub.2]*- or H[O.sub.2]* generates [H.sub.2][O.sub.2].
The international contributors of these nine papers describe a number of applications are avenues of research, including cobalt phosphine complexes for the polymerization of 1,3-diens (and the influence of the phosphine ligand on polymerization chemo- and stereo-selectivity), half-sandwich ruthenium complexes containing water-soluble phosphine ligands, ruthenium-silylene versus Ruthenium-n2-silane, activation of alkynes by camphor complexes, organic chemistry as a useful tool in the study of polyoxometalates, structural and biological chemistry of organtin (IV) complexes, the role of ionic liquids in palladium catalyzed C-C bond forming reactions methyl-migrational dismutation
of trimethyltin complexes, and siloxane-based polymeric structures containing complex metals.
The first might involve direct electron transfer from photoexcited molecules of HPD to oxygen to give [O.sub.2.sup.-*] that after dismutation
is converted into [H.sub.2][O.sub.2], a precursor of O[H.sup.*].
As well as arising from dismutation
of [O.sub.2.sup.-.], [H.sub.2] [O.sub.2] is produced by the action of several oxidase enzymes in vivo, including amino acid oxidases and the enzyme xanthine oxidases (10).
Superoxide dismutase catalyzes the dismutation
of the [O.sup.*-.sub.2] into [H.sub.2][O.sub.2] and [O.sub.2] (Elstner and Heupel, 1976).
2002 TNF RI (knock-out) Protected liver Crews 2001* TNF RII (knock-out) Gave no protection Crews 2001* NADPH Oxidase (knock-out) Protected liver Crews 2001* CD14 (knock-out) Protected liver Crews 2001* TLR4 (knock-out) Protected liver Crews 2001* ICAM (knock-out) Protected liver Crews 2001* CuZnSOD (dismutation
) (2) Protected liver Crews 2001* MnSOD (dismutation
) Protected liver Crews 2001* NOTE: CYP2E1 = cytochrome P450 2E1; TNF RI and II = tumor necrosis factor receptors I and II; NADH = reduced nicatinamide adenine dinucleotide; CD14 is an endotoxin receptor; TLR4 is a toll receptor that responds to endotoxin together with CD14; ICAM = cell adhesion molecule binding leukocytes; CuZnSOD = copper zinc superoxide dismutase; MnSOD = manganese superoxide dismutase.
Peptides synthetically obtained from combinatorial chemistry or enzymatic dismutation
of proteins are attracting attention because they provide specialty attributes in cosmetic products.