2Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, 119999 Moscow, Russia
* To whom correspondence should be addressed.
Received November 1, 2013; Revision received November 21, 2013
A partially purified Na,K-ATPase preparation from rat heart containing α1- and α2-isoforms of the enzyme was shown to include both subunits in S-glutathionylated state. Glutathionylation of the α1-subunit (but not of the α2-subunit) was partially removed when the preparation was isolated in the presence of dithiothreitol. The addition of oxidized glutathione irreversibly inhibited both isoforms. Inhibition of the enzyme containing the α1-subunit was biphasic, and the rate constants of the inhibition were 3745 ± 360 and 246 ± 18 M-1·min-1. ATP, ADP, and AMP protected the Na,K-ATPase against inactivation by oxidized glutathione.
KEY WORDS: Na,K-ATPase, glutathionylation, oxidized glutathione, rat heart