Ouabain-binding-site photoaffinity probes that label both subunits of Na+,K+-ATPase.

AUTOR(ES)

Hall, C

RESUMO

4"'-Diazomalonyldigitoxin and its isomer, 3"'-diazomalonyldigitoxin, have been synthesized at high specific radioactivity and used as photolabels for the Na,K-ATPase (ATP phosphohydrolase, EC 3.6.1.3) purified from Electrophorus electricus. Photoaffinity labeling experiments using both type I and type II complexes of enzyme with both photolabels showed ouabain-protectable labeling of the alpha as well as the beta subunit. These data suggest that, in the purified eel enzyme, the alpha and beta subunits are in intimate contact, at least in the region of the third digitoxose of the "sugar-specific" binding site.

Documentos Relacionados

• Photoaffinity Labeling of the Ouabain-Binding Site on (Na+ + K+) Adenosinetriphosphatase
• H2O2-induced uncoupling of bovine lens Na+,K+-ATPase.
• Partial Purification of the Ouabain-Binding Component and of Na,K-ATPase from Human Red Cell Membranes*
• Identification of a region within the Na,K-ATPase alpha subunit that contributes to differential ouabain sensitivity.
• High-affinity ouabain binding by yeast cells expressing Na+, K(+)-ATPase alpha subunits and the gastric H+, K(+)-ATPase beta subunit.