3-Bromopyruvate inhibits calcium uptake by sarcoplasmic reticulum vesicles but not SERCA ATP hydrolysis activity

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• 作者：Douglas Jardim-Messeder ; Juliana Camacho-Pereira ; Antonio Galina ; ^{galina@bioqmed.ufrj.br}
• 关键词：SRV ; sarcoplasmic reticulum vesicles ; SERCA ; sarco/endoplasmic reticulum calcium Ca2+ ATPase ; 3BrPA ; 3-bromopyruvate ; GSH ; reduced glutathione ; IAA ; iodoacetamide
• 刊名：The International Journal of Biochemistry and Cell Biology
• 出版年：2012
• 期刊代码：127_13572725
• 类别：med
• 出版时间：May, 2012
• 卷：44
• 期：5
• 页码：801-807
• 文件大小：648 K

摘要

3-Bromopyruvate (3BrPA) is an antitumor agent that alkylates the thiol groups of enzymes and has been proposed as a treatment for neoplasias because of its specific reactivity with metabolic energy transducing enzymes in tumor cells. In this study, we show that the sarco/endoplasmic reticulum calcium (Ca²⁺) ATPase (SERCA) type 1 is one of the target enzymes of 3BrPA activity. Sarco/endoplasmic reticulum vesicles (SRV) were incubated in the presence of 1 mM 3BrPA, which was unable to inhibit the ATPase activity of SERCA. However, Ca²⁺-uptake activity was significantly inhibited by 80%with 150 渭M 3BrPA. These results indicate that 3BrPA has the ability to uncouple the ATP hydrolysis from the calcium transport activities. In addition, we observed that the inclusion of 2 mM reduced glutathione (GSH) in the reaction medium with different 3BrPA concentrations promoted an increase in 40%in ATPase activity and protects the inhibition promoted by 3BrPA in calcium uptake activity. This derivatization is accompanied by a decrease of reduced cysteine (Cys), suggesting that GSH and 3BrPA increases SERCA activity and transport by pyruvylation and/or S-glutathiolation mediated by GSH at a critical Cys residues of the SERCA.