Sodium-Potassium-activated Adenosine Triphosphatase of Electrophorus Electric Organ
1973; Elsevier BV; Volume: 248; Issue: 3 Linguagem: Inglês
10.1016/s0021-9258(19)44335-4
ISSN1083-351X
AutoresR. Wayne Albers, George J. Koval,
Tópico(s)Molecular Junctions and Nanostructures
ResumoThe K+ activation of the p-nitrophenylphosphatase activity of Electrophorus electric organ (Na+-K+)-ATPase is characterized by a synergistic activation by Na+. This phenomenon does not require the presence of nucleotides, and it is markedly enhanced by dimethylsulfoxide. Analysis of the activation data leads to the conclusion that K+ activation in the absence of Na+ involves two different sets of binding sites, one of which regulates substrate accessibility to the phosphatase site and one of which acts to increase its catalytic potential. Na+ can replace K+ in the first instance, but is only 3% as effective as a catalytic activator. Na+ appears to exert its regulatory action through a distinct set of Na+ specific sites.
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