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The irreversible inactivation of two copper‐dependent monooxygenases by sulfite: peptidylglycine α‐amidating enzyme and dopamine β‐monooxygenase
Author(s) -
Merkler David J.,
Kulathila Raviraj,
Francisco Wilson A.,
Ash David E.,
Bell Joseph
Publication year - 1995
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(95)00516-c
Subject(s) - monooxygenase , chemistry , sulfite , enzyme , dopamine , biochemistry , copper , stereochemistry , biology , organic chemistry , cytochrome p450 , endocrinology
Peptidylglycine α‐amidating enzyme (α‐AE) and dopamine β‐monooxygenase (DβM), two copper‐dependent monooxygenases that have catalytic and structural similarities, are irreversibly inactivated by sodium sulfite in a time‐ and concentration‐dependent manner. Studies with α‐AE show that the sulfite‐mediated inactivation is dependent on the presence of redox active transition metals free in solution, with Cu(II) being the most effective in supporting the inactivation reaction. Sulfite inactivation of α‐AE is specific for the monooxygenase reaction of this bifunctional enzyme and amidated peptides provide protection against the inactivation. Consequently, the sulfite‐mediated inactivation of α‐AE and DβM most likely results from the transition metal‐catalyzed oxidation of sulfite to the sulfite radical, SO 3 − .