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Primary structure of a cationic Cu,Zn Superoxide dismutase
Author(s) -
Schininà M.E.,
Barra D.,
Gentilomo S.,
Bossa F.,
Capo C.,
Rotilo G.,
Calabrese L.
Publication year - 1986
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(86)80003-5
Subject(s) - enzyme , superoxide dismutase , active site , chemistry , biochemistry , cationic polymerization , dismutase , amino acid , enzyme assay , organic chemistry
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.