title: Reversible inactivation of (Na+ + K+)-ATPase by use of a cleavable bifunctional reagent.
abstract: 1. Purified (Na+ + K+)-ATPase, prepared from rabbit kidney outer medulla, is incubated with the bifunctional NH2-directed reagent dimethyl 3,3'-dithiobis-propionimidate. This results in a cross-link between the subunits of the enzyme and a simultaneous reduction of the (Na+ + K+)-ATPase and K+-stimulated p-nitrophenylphosphatase activities. 2. The most abundant cross-link product is a dimer of the two different subunits of the enzyme. 3. Reduction of the disulfide cross-link by dithioerythritol results in partial recovery of the original subunit structure of the enzyme and of the (Na+ + K+)-ATPase and K+-stimulated p-nitrophenylphosphatase activities. 4. These results suggest that a free mobility of the subunits of the (Na+ + K+)-ATPase system relative to each other is essential for proper functioning of both enzyme activities.
mesh_terms: D009597:4-Nitrophenylphosphatase / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D004220:Disulfides / Q000494:pharmacology; D004226:Dithioerythritol / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007094:Imides / Q000494:pharmacology*; D066298:In Vitro Techniques; D007202:Indicators and Reagents / Q000494:pharmacology; D011487:Protein Conformation / Q000187:drug effects; D011817:Rabbits; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
chemical_list: D004220:Disulfides; D007094:Imides; D007202:Indicators and Reagents; D004226:Dithioerythritol; D009597:4-Nitrophenylphosphatase; D000254:Sodium-Potassium-Exchanging ATPase