Evidence for the involvement of (Cu-ATP)2- in the inhibition of human erythrocyte (Ca2+ + Mg2+)-ATPase by copper.
Biochim Biophys Acta
; 775(1): 51-6, 1984 Aug 08.
Article
en En
| MEDLINE
| ID: mdl-6147158
The effects of copper on the activity of erythrocyte (Ca2+ + Mg2+)-ATPase have been tested on membranes stripped of endogenous calmodulin or recombined with purified calmodulin. The interactions of copper with Ca2+, calmodulin and (Mg-ATP)2- were determined by kinetic studies. The most striking result is the potent competitive inhibition exerted by (Cu-ATP)2- against (Mg-ATP)2- (Ki = 2.8 microM), while free copper gives no characteristic inhibition. Our results also demonstrate that copper does not compete with calcium either on the enzyme or on calmodulin. The fixation of calmodulin on the enzyme is not altered in the presence of copper as shown by the fact that the dissociation constant remains unaffected. It may be speculated that (Cu-ATP)2- is the active form of copper, which could plausibly be at the origin of some of the pathological features of erythrocytes observed in conditions associated with excess copper.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
ATPasas Transportadoras de Calcio
/
Cobre
/
Eritrocitos
Límite:
Humans
Idioma:
En
Revista:
Biochim Biophys Acta
Año:
1984
Tipo del documento:
Article
Pais de publicación:
Países Bajos