Open AccessThe Effect of Fluoride on the Spectral and Catalytic Properties of Three Copper‐Containing Oxidases
Author(s) -
BrÄNDÉN Rolf,
MalmstrÖM Bo G.,
Vänngård Tore
Publication year - 1973
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1973.tb02901.x
Subject(s) - laccase , chemistry , copper , enzyme , electron paramagnetic resonance , intramolecular force , catalysis , substrate (aquarium) , kinetics , reaction rate constant , stereochemistry , organic chemistry , nuclear magnetic resonance , biology , ecology , physics , quantum mechanics
1 The optical spectra of fungal laccase, lacquer tree laccase and ceruloplasmin are changed in a similar way when F – is added to the proteins at pH 5.5. 2 A change around 320 nm is associated with the binding of F – to type 2 Cu 2+ of the proteins as seen from a correlation with electron paramagnetic resonance spectra. 3 The rate of binding of F – to fungal laccase is first order with respect to uncomplexed enzyme and independent of the F – concentration, indicating that an intramolecular process is rate limiting. The stability constant of the enzyme · F – complex is greater than 10 μM ‐1 . 4 Fungal laccase is almost completely inhibited when 1 equivalent of F – is bound to the type 2 Cu 2+ . Presence of substrate gradually decreases the inhibition, due to the release of F – from a reduced form of the enzyme.