Stimulation of the Ca2+-ATPase of sarcoplasmic reticulum by disulfiram

Abstract

Disulfiram [bis(diethylthiocarbamoyl)disulphide] has been found to stimulate reversibly the Ca(2+)-ATPase of skeletal muscle sarcoplasmic reticulum. At pH 7.2, 2.1 mM ATP and 25 degrees C, ATPase activity was found to double on addition of 120 microM disulfiram. Stimulation fitted to binding of disulfiram at a single site with a Kd of 61 microM. Disulfiram had no effect on the Ca2+ affinity of the ATPase or on the rate of phosphorylation of the ATPase by ATP, but increased the rate of dissociation of Ca2+ from the phosphorylated ATPase (the transport step) and increased the rate of dephosphorylation of the phosphorylated ATPase. It also decreased the level of phosphorylation of the ATPase by Pi, consistent with a 7.5-fold decrease in the equilibrium constant of the phosphorylated to non-phosphorylated forms (E2PMg/E2PiMg) at 80 microM disulfiram. Disulfiram had no significant effect on the concentration of ATP resulting in stimulation of ATPase activity, suggesting that it does not bind to the empty nucleotide-binding site on the phosphorylated ATPase. Studies of the effects of mixtures of disulfiram and jasmone (another molecule that stimulates the ATPase) suggest that they bind to separate sites on the ATPase.

Oxidative injury induced by hypochlorous acid to Ca-ATPase from sarcoplasmic reticulum of skeletal muscle and protective effect of trolox

“…These radicals are key species in HOCl-induced protein backbone fragmentation and dimerisation. FITC binding is localised to a specific lysine residue (Lys 515 ) located in the adenine nucleotide binding site of Ca-ATPase (Hidalgo et al 1982;Starling et al 1996;Schertzer et al 2003;Montigny et al 2007;Winters et al 2008). Reaction of the Ca-ATPase with FITC leads to inhibition of ATPase activity as the result of selective modification of the nucleotide binding site .…”

IgE-dependent human basophil responses are inversely associated with the sarcoplasmic reticulum Ca2+-ATPase (SERCA)

“…However, these inhibitory effects were moderate (<50% inhibition) and observed only after long (24h) preincubations with bafilomycin A1. It therefore remains questionable whether the potential inhibitory effects of disulfiram on V-ATPase in basophils is relevant considering the short preincubations (15 min) used in the present study where IgE-dependent histamine release was inhibited within previously published concentrations of the drug required for SERCA stimulation ( 40 ).…”

Effects of sevoflurane and its metabolite hexafluoroisopropanol on hypoxia/reoxygenation-induced injury and mitochondrial bioenergetics in murine cardiomyocytes

“…Disulfiram activates the sarco-endoplasmatic reticulum calcium ATPase (SERCA). 41 Calcium is crucial for myocardial contractility and impacts on apoptosis. In these experiments, neither intracellular calcium levels nor SERCA activity have been determined.…”