Open AccessModulation of sarcoplasmic reticulum Ca 2+ ‐ATPase by chronic and acute exposure to peroxynitrite
Author(s) -
GutiérrezMartín Yolanda,
MartínRomero Francisco J.,
IñestaVaquera Francisco A.,
GutiérrezMerino Carlos,
Henao Fernando
Publication year - 2004
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.2004.04193.x
Subject(s) - peroxynitrite , endoplasmic reticulum , atpase , chemistry , ryanodine receptor 2 , acute exposure , biophysics , modulation (music) , medicine , endocrinology , biochemistry , biology , physics , enzyme , ryanodine receptor , superoxide , acoustics
The Ca 2+ ‐ATPase of skeletal muscle sarcoplasmic reticulum (SERCA), an integral membrane protein, becomes irreversibly inactivated in vitro by the addition of a single bolus of peroxynitrite with a K 0.5 of 200–300 µ m , and this results in a large decrease of the ATP‐dependent Ca 2+ gradient across the sarcoplasmic reticulum (SR) membranes. The inactivation of SERCA is raised by treatment of SR vesicles with repetitive micromolar pulses of peroxynitrite. The inhibition of the SERCA is due to the oxidation of thiol groups and tyrosine nitration. Scavengers that react directly with peroxynitrite, such as cysteine, reduced glutathione, NADH, methionine, ascorbate or Trolox, a water‐soluble analog of α‐tocopherol, afforded significant protection. However, dimethyl sulfoxide and mannitol, two hydroxyl radical scavengers, and α‐tocopherol did not protect SERCA from inactivation. Our results showed that the target of peroxynitrite is the cytosolic globular domain of the SERCA and that major skeletal muscle intracellular reductants (ascorbate, NADH and reduced glutathione) protected against inhibition of this ATPase by peroxynitrite.