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Mutation of Lys‐120 and Lys‐134 drastically reduces the catalytic rate of Cu,Zn superoxide dismutase
Author(s) -
Polticelli Fabio,
Battistoni Andrea,
Bottaro Grazia,
Carri Maria Teresa,
O'Neill Peter,
Desideri Alessandro,
Rotilio Giuseppe
Publication year - 1994
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(94)00885-x
Subject(s) - superoxide dismutase , chemistry , catalysis , dismutase , superoxide , copper , substrate (aquarium) , threonine , biochemistry , enzyme , serine , biology , organic chemistry , ecology
Lys‐120 and Lys‐134, located at the edge of the active site channel in most Cu,Zn superoxide dismutases, have been suggested to play a major role in steering the anionic substrate towards the catalytic copper ion. In this study, mutants of Xenopus laevis Cu,Zn superoxide dismutase have been engineered, with Lys‐120 and Lys‐134 changed into leucine and threonine, respectively, and their catalytic properties have been investigated by pulse radiolysis. Results obtained demonstrate that both residues decrease the catalytic rate by about 40%, in partial disagreement with previous brownian dynamics calculations, carried out on bovine Cu,Zn superoxide dismutase.