Superoxide anions

One of the important consequences of neuronal stimulation is increased neuronal aerobic metabolism which produces reactive oxygen species (ROS). ROS can oxidize several biomoiecules (carbohydrates, DNA, lipids, and proteins). Thus, even oxygen, which is essential for aerobic life, may be potentially toxic to cells. Addition of one electron to molecular oxygen (O,) generates a free radical [O2)) the superoxide anion. This is converted through activation of an enzyme, superoxide dismurase, to hydrogen peroxide (H-iO,), which is, in turn, the source of the hydroxyl radical (OH). Usually catalase... 

Luminescence reaction. Pholasin undergoes an oxidative luminescence reaction in the presence of any of the following substances Pholas luciferase, ferrous ions, H2O2, peroxidases, superoxide anions, hypochlorite and other oxidants. In all cases, molecular oxygen is required and pholasin is converted into oxypholasin in the reaction. 

When H2O2 is a necessary component of a luminescence system, it can be removed by catalase. If a luminescence system involves superoxide anion, the light emission can be quenched by destroying O2 with superoxide dismutase (SOD). The ATP cofactor usually present in the fresh extracts of the fireflies and the millipede Luminodesmus can be used up by their spontaneous luminescence reactions, eventually resulting in dark (nonluminous) extracts containing a luciferase or photoprotein. The process is, however, accompanied by a corresponding loss in the amount of luciferin or photoprotein. The use of ATPase and the elimination of Mg2+ in the extract may prevent such a loss. 

Colepicolo, P., et al. (1990). A sensitive and specific assay for superoxide anion released by neutrophils or macrophages based on bioluminescence of polynoidin. Anal. Biochem. 184 369-374. 

Lucas, M., and Solano, F. (1992). Coelenterazine is a superoxide anion-sensitive chemiluminescent probe its usefulness in the assay of respiratory burst in neutrophils. Anal. Biochem. 206 273-277. 

Nakano, M., Sugioka, K., Ushijima, Y., and Goto, T. (1986). Chemiluminescence probe with Cypridina luciferin analogue, 2-methyl-6-phenyl-3,7-dihydroimidazo[l,2-a]pyrazine-3-one, for estimating the ability of human granulocytes to generate superoxide anion. Anal. Biochem. 159 363-369. 

Nishinaka, Y., et al. (1993). A new sensitive chemiluminescence probe, L-012, for measuring the production of superoxide anion by cells. Biocbem. Biophys. Res. Commun. 193 554—559. 

Shimomura, O. (1993). The role of superoxide anion in bioluminescence. In Shima, A., etal. (eds.), Frontiers of Photobiology, pp. 249-254. Elsevier Science Publishers, Amsterdam. 

Shimomura, O., Wu, C., Murai, A., and Nakamura, H. (1998). Evaluation of five imidazopyrazinone-type chemiluminescent superoxide probes and their application to the measurement of superoxide anion generated by Listeria monocytogenes. Anal. Biochem. 258 230-235. 

Storch, J., and Ferber, E. (1988). Detergent-amplified chemiluminescence of lucigenin for determination of superoxide anion production by NADPH oxidase and xanthine oxidase. Anal. Biochem. 169 262-267. 

Teranishi, K. (2003). Cyclodextrin-bound 6-(4-methoxyphenyl)imidazo[l,2-a]-pyrazin-3(7H)-one as chemiluminescent probe for superoxide anions. ITE Letters on Batteries, New Technologies and Medicine 4 201-205. 

Teranishi, K., and Shimomura, O. (1997b). Coelenterazine analogs as chemiluminescent probe for superoxide anion. Anal. Biochem. 249 37-43. 

A potent oxidant that is formed by NO reacting with superoxide anions. 

Superoxide dismutase (SOD) enzymes are metallopro-teins that detoxify superoxide anions (02) by converting them to H202, which is subsequently reduced to water. SOD enzymes include the manganese (Mn) enzyme in mitochondria (SOD2) and the Cu/Zn... 

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