Electrophorus Adenosine Triphosphatase: Sodium-Activated Exchange after N-Ethyl Maleimide Treatment

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Science  17 Jul 1964:
Vol. 145, Issue 3629, pp. 283-284
DOI: 10.1126/science.145.3629.283


The microsomal fraction from the electric organ of the eel Electrophorus electricus catalyzes the hydrolysis of adenosine triphosphate in the presence of Mg++, Na+, and K+. The same preparation catalyzes a Mg++-dependent transphosphorylation between adenosine triphosphate and adenosine diphosphate. Both of these reactions are inhibited after treatment of the microsomes with N-ethyl maleimide. However, the addition of Na+ reactivates the transphosphorylation, and the rate becomes more rapid than that of the original. This new Na+-sensitive exchange reaction is believed to be a component of the hydrolytic reaction.