Open AccessInhibition of Ceruloplasmin by Inorganic Anions
Author(s) -
GUNNARSSON PerOlov,
Nylén Ulf,
PETTERSSON Gösta
Publication year - 1972
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1972.tb01874.x
Subject(s) - ceruloplasmin , cyanate , chemistry , azide , substrate (aquarium) , bromide , enzyme , inorganic chemistry , ternary complex , chloride , medicinal chemistry , polymer chemistry , biochemistry , organic chemistry , oceanography , geology
The steady‐state rate behaviour of ceruloplasmin in the presence of inhibitory inorganic anions (azide, cyanate, fluoride, chloride and bromide) has been studied in detail. Formation of ternary enzyme · substrate · inhibitor complexes was found to be kinetically insignificant, which most likely indicates that enzyme · substrate complexes are kinetically insignificant also in absence of inhibitors. Equilibrium constants for the inhibitory binding of inorganic anions to oxidized and reduced ceruloplasmin were estimated kinetically (Table 1) in view of a simplified model mechanism described elsewhere. Halogenide ions were found to interact with both oxidized and reduced ceruloplasmin, although inhibition mainly occurs through complex formation with reduced form of the enzyme. Inhibition by azide and cyanate are, similarly, due to strong interactions with a reduced form of ceruloplasmin, whereas complex formation involving oxidized enzyme was found to be kinetically insignificant at low concentrations of inhibitor.