Gel electrophoretic identity of the (Na+ + Mg-2+)- and (Na+ + Ca-2+)-stimulated phosphorylations of rat brain ATPase.
Biochim Biophys Acta, 1975/4/21;389(1):117-25.
PMID: 124586
Abstract
The classical E2-P intermediate of (Na+ + K+)-ATPase dephosphorylates readily in the presence of K+ and is not affected by the addition of ADP. To determine the significance in the reaction cycle of (Na+ + K+)-ATPase of kinetically atypical phosphorylations of rat brain (Na+ + K+)-ATPase we compared these phosphorylated components with the classical E2-P intermediate of this enzyme by gel electrophoresis. When rat brain (Na+ + K+)-ATPase was phosphorylated in the presence of high concentrations of Na+ a proportion of the phosphorylated material formed was sensitive to ADP but resistant to K+. Similarly, if phosphorylation was carried out in the presence of Na+ and Ca-2+ up to 300 pmol/mg protein of a K+ -resistant, ADP-sensitive material were formed. If phosphorylation was from [gamma-32-P]CTP up to 800 pmol-32-P/mg protein of an ADP-resistant, K+ -sensitive phosphorylated material were formed. On gel electrophoresis these phosphorylated materials co-migrated with authentic Na+ -stimulated, K+ -sensitive, E2-P-phosphorylated intermediate of (Na+ + K+)-ATPase, supporting suggestions that they represent phosphorylated intermediates in the reaction sequence of this enzyme.
MeSH terms
Adenosine Diphosphate; Adenosine Triphosphatases; Adenosine Triphosphate; Animals; Brain; Calcium; Cytosine Nucleotides; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; Magnesium; Potassium; Rats; Sodium
More resources
EndNote: Download