Superoxide dismutase bovine

FIGURE 10.6 Comparison of solid-state and liquid-state spectra from a copper protein. The figure illustrates shifts in apparent gz and Az-values of the S = 1/2 and I =3/2 spectrum from Cu11 in bovine superoxide dismutase as a function of the surrounding medium. Top trace frozen aqueous solution at 60 K middle trace frozen water/glycerol (90/10) solution at 60 K bottom trace aqueous solution at room temperature. (Modified from Hagen 1981.)... 

M.E. Me Adam, E.M. Fielden, F. Favelle, F. Calabrese, D. Cocco, and G. Rotilio, The involvement of the bridging imidazolate in the catalytic mechanism of action of bovine superoxide dismutase. 

Cockle, S. A., Bray, R. C. Do all the copper atoms in bovine superoxide dismutase function in catalysis In Superoxide and Superoxide Dismutases (Michelson, A. M., McCord, J, M., Fridovich, L, eds.), London-New York-San Francisco, Academic Press, 1977, pp. 215-216... 

Zepp, R. A., Chelack, W. S., Petkau, A. Bovine superoxide dismutase preparations Comparison of their biochemical and biological characteristics. In Chemical and Biochemical Aspects of Superoxide and Superoxide Dismutase (Bannister, J. V., Hill, H. A. O., eds.). New York-Amsterdam-Oxford, Elsevier/North-Holland, 1980, pp. 201-211 Rigo, A. et al. Biochem. J. 161, 27 (1977)... 

When metal ions with unimpaired electrons are used, compounds with interesting magnetic structures may be observed,28 e.g. dimers,29 trimers,30 tetramers,31 pentamers,32 linear chains33 and also two-dimensional layered compounds.34 An imidazolato bridge is known to be present in the enzyme bovine superoxide dismutase.35... 

Usually the enzymes are given an Enzyme Classification (EC) number, consisting of three or four figures separated by dots, to indicate subgroup and subsubgroup (e.g., bovine superoxide dismutase [SOD], EC 1.15.1.1). The enzymes discussed in the present monograph are given with their EC numbers in the Abbreviations section. 

Fig. 5-5. Schematic drawing of the active site of bovine superoxide dismutase.

Figure 5. Possible bridge-splitting mechanism for bovine superoxide dismutase activity...

Klug-Roth D, Fridovich I, Rabani J. (1973) Pulse radiolytic investigations of superoxide catalyzed disproportionation. Mechanism for bovine superoxide dismutase. J Am Chem Soc 95 2786-2790. 

FIGURE 16-12 Active Site of Bovine Superoxide Dismutase. Shown is a drawing of the active site channel as viewed from the solvent. The main chain is shown in black, the ligand side chains as open circles and bonds, and the other side chains as solid atoms and open bonds. (Reproduced with permission from J. A. Tainter, E. D. Getzoff,... 

Bovine Superoxide Dismutase and Its Association from Bovine Heart, /. Biol Chem, (1971) 246, 2875-2880. 

It has been concluded from a study of the optical and e.p.r. spectra of Co —Cu bovine superoxide dismutase, in which zinc has been replaced by cobalt, that the cobalt site reactivity should be described in terms of reaction of the Co-imidazolate-Cu system as a whole the crystal structure reported last year indicated that the metals were linked by a common histidine residue. There is an exchange interaction between the cobalt and copper however, this is abolished when the linking imidazole is protonated. Further evidence for the close proximity and interactive dependence of the zinc and copper binding sites was obtained from a study of the 4 Cu protein a two-fold enhancement of the activity of 2 Cu dismutase was observed upon occupation of the zinc sites by the Cu ". On the basis of C1 n.m.r. studies, Fee and Ward have suggested that one co-ordination position of Cu in superoxide dismutase is normally occupied by water they further suggest that superoxide can displace the solvent to form a cupric peroxide complex. 

The dismutation of O2 by iron superoxide dismutase was found to be similar to that for the copper/zinc bovine superoxide dismutase. The results obtained by Lavelle et al. (1977) showed that catalysis of dismutation of O2 by the iron superoxide dismutase from Photobacterium leiognathi is first order with respect to substrate concentration for all ratios of substrate to enzyme concentrations reported. Although the enzyme is stable between pH 6.0 and 10.0, the value of the rate constant decreases as the pH increases. The second-order rate constant for the reaction be-... 

Fig. 3. Effect of concentration of bovine superoxide dismutase on oxygen wave at pH 9. 76 in presence of triphenylphosphine oxide. (1) without superoxide dismutase (2) superoxide dismutase = 1.4 x (3) superoxide dismutase =...

Fig. 4. Left side of Koutecky equation plotted versus the bovine superoxide dismutase concentration. Sodium tetraborate 0.025 Af triphenylphosphineoxide 0.025% (wt.) pH = 9.76 tg = 2.90sec temperature = 25°C. (Reprinted with permission from A. Rigo etal., icc(roanai. Chem. Inlerfac. Electrochem.,57,291-296, 1974.)...

Cadmium-113 nuclear magnetic resonance studies of the cadmium substituted bovine superoxide dismutase were carried out Only a very small chemical-shift difference between the 2 Cd(Il) protein (Cd(II) is bound to the zinc site and the copper site is unoccupied) and the 2 Cd(ll)—2 Cu(I) enzyme (analogous to the reduced form of the native protein) was found. This was interpreted in that the imidazolate bridge is protonated at the Cu site after reduction. 

The kinetics of formation of the intermediate complex between catalase and HgOa have been re-examined, and reports of pulse radiolysis experiments with superoxide dismutase and its manganese-containing form have appeared. Bovine superoxide dismutase is known to contain two Cu and two Zn atoms per molecule and it has been shown that the copper site, which is directly involved in the catalytic activity, comprises three nitrogens and a water molecule bound to the metal in a field with less than axial symmetry. Less is known of the zinc site but it has recently been shown, by e.p.r. spectroscopy with the cobalt-copper form of the enzyme, that the... 

Lieberman RA, Sands RH, Fee JA. 1982. A study of the electron paramagnetic resonance properties of single monocbnic crystals of bovine superoxide dismutase. J Biol Chem 257 336-344. 

Bovine superoxide dismutase and catalase were purchased from Sigma Chemical Co., glutathione peroxidase from Boehringer Mannheim and quinoxaline from Fluka AG. The synthesis of 6,7-dimethylperin and its 7,8-dihydro derivative has been described before. 6,7-Dimethyl-5,6,7,8-tetra-hydropterin was prepared by controlled potential electrolysis a 0.1 M phosphate buffer pH 7.0 at a glassy carbon or a mercury pool cathode. After complete electrolysis the tetrahydropterin was used in situ. 1,2,3,4-Tetrahydroquinoxaline was prepared by reducing quinoxaline in dry ether with lithium aluminium hydride or in ethanol with solid sodium. ... 

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