Modulation of the low affinity Ca2+-binding sites of skeletal muscle and blood platelets Ca2+-ATPase by nordihydroguaiaretic acid
| 详细信息 | 推荐本文 | |
- 作者：Hosana Barata ; Cristiana M. Cardoso ; Herman Wolosker and Leopoldo de Meis
- 关键词：Ca2+ ; ATPase ; nordihydroguaiaretic acid ; Ca2+ affinity
- 刊名：Molecular and Cellular Biochemistry
- 出版时间：1999
- 出版年：1999
- 期刊代码：38_03008177
- 类别：cp
- 卷：195
- 期：1/2
- 页码：227-233
- 数据来源：sp
摘要
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.