Primary structure of a cationic Cu,Zn Superoxide dismutase: The sheep enzyme

• Published in: FEBS letters Vol. 207; no. 1; pp. 7 - 10
• Main Authors: Schininà, M.E., Barra, D., Gentilomo, S., Bossa, F., Capo, C., Rotilo, G., Calabrese, L.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 20.10.1986; Elsevier
• Subjects: Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Cattle; Electrostatic interaction; Enzymes and enzyme inhibitors; Erythrocyte; erythrocytes; Fundamental and applied biological sciences. Psychology; Oxidoreductases; Sheep; Superoxide dismutase; Superoxide Dismutase - analysis; Erythrocyte; Amino acid sequence; Superoxide dismutase; Sheep; Electrostatic interaction; Vertebrata; Mammalia; Enzyme; Active site; Red blood cell; Primary structure; Artiodactyla; Ungulata
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(86)80003-5

The complete amino acid sequence of Cu,Zn Superoxide dismutase from sheep erythrocytes has been determined. The sequence is very similar to that of the bovine enzyme, having the same number of residues (151) and only two substitutions in the ‘hypervariable’ region (residues 17–30). The 5 overall substitutions confer a positive charge on the sheep enzyme at neutral pH (p I≈8). This charge is localized outside the active site region. The catalytic efficiency of the sheep enzyme is 15% less than that of the cow enzyme, confirming the hypothesis that the enzyme activity is related to the concentration of positive surface charge near the active site channel.