scholarly journals Investigation of human erythrocyte superoxide dismutase by 1H nuclear-magnetic-resonance spectroscopy

1980 ◽  
Vol 185 (1) ◽  
pp. 245-252 ◽  
Author(s):  
H A O Hill ◽  
W K Lee ◽  
J V Bannister ◽  
W H Bannister
Keyword(s):  
Superoxide Dismutase ◽  
Active Site ◽  
Human Erythrocyte ◽  
Superoxide Dismutases ◽  
Resonance Spectroscopy ◽  
Structural Homology ◽  
Histidine Residues ◽  
Erythrocyte Superoxide Dismutase ◽  
1H Nuclear Magnetic Resonance ◽  
Acetyl Group

The 170MHZ 1 H n.m.r. spectra of the Cu(II)/Zn(II), Cu(I)/Zn(II) and apo- forms of human erythrocyte superoxide dismutase (EC 1.15.1.1) are reported. Resonances are assigned to the C-2 and C-4 protons of histidine residues in the active site, and it is suggested that five or six histidine residues serve as ligands to the metal ions in each subunit of the enzyme. The remaining assigned resonances are associated with histidine-41, N-terminal N-acetyl group, histidine- 108 and cysteine- 109. A comparison of the n.m.r. spectra of human and bovine superoxide dismutases suggests significant structural homology.

scholarly journals Carbon-2 proton exchange at histidine-41 in bovine erythrocyte superoxide dismutase

1977 ◽  
Vol 165 (3) ◽  
pp. 587-589 ◽  
Author(s):  
A E G Cass ◽  
H A O Hill ◽  
B E Smith ◽  
J V Bannister ◽  
W H Bannister
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Superoxide Dismutase ◽  
Peptide Mapping ◽  
Proton Exchange ◽  
Resonance Spectroscopy ◽  
Histidine Residue ◽  
Protein Digestion ◽  
Bovine Erythrocyte ◽  
Erythrocyte Superoxide Dismutase ◽  
1H Nuclear Magnetic Resonance

The C-2 proton of one histidine residue in bovine erythrocyte superoxide dismutase is shown to be particularly labile. This residue is identified by tritiation, protein digestion and subsequent peptide ‘mapping’ as histidine-41. A half-life for the exchange of histidine C-2 1H for 2H in 2H2O as solvent, at pD 8.1 and 40 degrees C, is estimated as approx. 9.2h, by 1H nuclear-magnetic-resonance spectroscopy.

Superoxide Dismutase Inactivation by Radiation-Induced Radicals: Evidence for Histidine Residues in the Active Site

1974 ◽  
Vol 60 (3) ◽  
pp. 441 ◽  
Author(s):  
P. B. Roberts ◽  
E. M. Fielden ◽  
G. Rotilio ◽  
L. Calabrese ◽  
J. V. Bannister ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Active Site ◽  
Histidine Residues ◽  
Radiation Induced

scholarly journals pH-dependent inhibition by azide and fluoride of the iron superoxide dismutase from Propionibacterium shermanii

1998 ◽  
Vol 331 (2) ◽  
pp. 403-407 ◽  
Author(s):  
Beate MEIER ◽  
Christoph SCHERK ◽  
Marius SCHMIDT ◽  
Fritz PARAK
Keyword(s):  
Superoxide Dismutase ◽  
Active Site ◽  
Low Ph ◽  
Superoxide Dismutases ◽  
Iron Superoxide Dismutase ◽  
Propionibacterium Shermanii ◽  
Hydroxyl Anion ◽  
Dependent Inhibition ◽  
Ph Dependent ◽  
A Minor

The iron-containing superoxide dismutase from Propionibacterium shermanii shows, in contrast with other iron superoxide dismutases, only a minor inhibition by azide or fluoride (10–100 mM) of up to 23% at pH 7.8. The activity of the protein with Mn bound to the active site was not diminished under the same conditions. The binding constant between azide and the Fe3+ ion was determined as approx. 2 mM and for fluoride approx. 2.3 mM; they are so far comparable to those known for other iron superoxide dismutases. This seems to be a discrepancy because all other iron superoxide dismutases so far known are described as being inhibited by 50–70% by 10 mM azide. However, towards lower pH there was a drastically increased inhibition by both anions. At pH 6.8 about 80% inhibition was exhibited by azide or fluoride at a concentration of 10 mM or higher. In contrast, on increasing the pH, azide or fluoride still bound to the Fe3+ at the active site but their inhibition capacity decreased. This observation implies that both anions bind to the metal at a position that is empty at low pH, whereas at higher pH water or a negatively charged hydroxyl anion is bound. It is likely that the superoxide anion binds to the same position and has to replace the sixth ligand, leading to a diminished catalytic activity of the superoxide dismutase owing to steric and/or electrostatic inhibition of the ligand.

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