Modulation of the low affinity Ca2+-binding sites of skeletal muscle and blood platelets Ca2+-ATPase by nordihydroguaiaretic acid.
Mol Cell Biochem
; 195(1-2): 227-33, 1999 May.
Article
em En
| MEDLINE
| ID: mdl-10395087
ABSTRACT
The antioxidant nordihydroguaiaretic acid (NDGA) inhibited the different sarco/endoplasmic reticulum Ca2+-ATPase isoforms found in skeletal muscle and blood platelets. For the sarcoplasmic reticulum, but not for the blood platelets Ca2+-ATPase, the concentration of NDGA needed for half-maximal inhibition was found to vary depending on the substrate used and its concentration in the assay medium. The phosphorylation of the sarcoplasmic reticulum Ca2+-ATPase by ATP and by Pi were both inhibited by NDGA. In leaky vesicles, measurements of the ATP<-->Pi exchange showed that NDGA increases the affinity for Ca2+ of the E2 conformation of the enzyme, which has low affinity for Ca2+. The effects of NDGA on the Ca2+-ATPase were not reverted by the reducing agent dithiothreitol nor by the lipid-soluble antioxidant butylated hydroxytoluene.
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Base de dados:
MEDLINE
Assunto principal:
Plaquetas
/
Masoprocol
/
Cálcio
/
ATPases Transportadoras de Cálcio
/
Músculo Esquelético
Idioma:
En
Ano de publicação:
1999
Tipo de documento:
Article