Display Settings:


Send to:

Choose Destination
See comment in PubMed Commons below
Biochem Biophys Res Commun. 2007 Apr 27;356(1):142-6. Epub 2007 Mar 1.

Role of homologous ASP334 and GLU319 in human non-gastric H,K- and Na,K-ATPases in cardiac glycoside binding.

Author information

  • 1Department of Physiology, Pharmacology, Metabolism, and Cardiovascular Sciences, University of Toledo College of Medicine, Toledo, OH 43614, USA.


Cardiac steroids inhibit Na,K-ATPase and the related non-gastric H,K-ATPase, while they do not interact with gastric H,K-ATPase. Introducing an arginine, the residue present in the gastric H,K-ATPase, in the second extracellular loop at the corresponding position 334 in the human non-gastric H,K-ATPase (D334R mutation) rendered it completely resistant to 2mM ouabain. The corresponding mutation (E319R) in alpha1 Na,K-ATPase produced a approximately 2-fold increase of the ouabain IC(50) in the ouabain-resistant rat alpha1 Na,K-ATPase and a large decrease of the ouabain affinity of human alpha1 Na,K-ATPase, on the other hand this mutation had no effect on the affinity for the aglycone ouabagenin. These results provide a strong support for the orientation of ouabain in its biding site with its sugar moiety interacting directly with the second extracellular loop.

[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science Icon for PubMed Central
    Loading ...
    Write to the Help Desk