Open AccessOuabain-binding-site photoaffinity probes that label both subunits of Na+,K+-ATPase.
Author(s) -
Clifford C. Hall,
Arnold E. Ruoho
Publication year - 1980
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.77.8.4529
Subject(s) - electrophorus , photoaffinity labeling , protein subunit , affinity label , ouabain , chemistry , enzyme , atpase , binding site , affinity labeling , g alpha subunit , biochemistry , stereochemistry , receptor , sodium , torpedo , acetylcholine receptor , organic chemistry , gene
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.