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Role of the reductant substrates on the inactivation of horseradish peroxidase by m‐Chloroperoxybenzoic acid
Author(s) -
Arnao M. B.,
GarciaCánovas F.,
Acosta M.
Publication year - 1996
Publication title -
iubmb life
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.132
H-Index - 113
eISSN - 1521-6551
pISSN - 1521-6543
DOI - 10.1080/15216549600201101
Subject(s) - horseradish peroxidase , peroxidase , substrate (aquarium) , chemistry , enzyme , catalysis , combinatorial chemistry , biochemistry , organic chemistry , biology , ecology
Horseradish peroxidase reacts with H2O2 and other hydroperoxides to form Compound I, the first active enzymatic form. m‐Chloroperoxybenzoic acid, a xenobiotic hydroperoxide, acts as an oxidant substrate of horseradish peroxidase. However, this hydroperoxide is also a powerful inactivator of the enzyme and in this sense is more effective than H2O2. The coupled reductant substrates used in the peroxidatic reaction protect the enzyme from the inactivating process. A reaction mechanism is proposed with two competitive routes: one catalytic and one inactivating. Using a kinetic approach, the ratio between the hydroperoxide and the reductant substrate appears to be a decisive factor in the catalytic turnover of the enzyme. The role of the reductant substrates in protecting the enzyme, and the physiological and biotechnological implications of this process are discussed.