Effect of Mg2+-ATP on acetylcholinesterase of Electrophorus electricus (L)

The effect of Mg2+-ATP on purified acetylcholinesterase (AChE) from electric tissue of Electrophorus electricus ( L.) was studied. The enzymatic activities were measured with acetylcholine and acetylthiocholine as substrates. The kinetic parameters V-max, K-m and Hill coefficient (n(H)), for acetylcholine and acetylthiocholine were modified with Mg2+-ATP. It was shown that acetylcholinesterase presents an apparent activation at high concentration of substrates and an inhibition in the presence of Mg2+-ATP at low concentration of acetylcholine and acetylthiocholine. In addition, the data suggest that Mg2+-ATP induced an allosteric modulation of the acetylcholinesterase obtained from Electrophorus electricus (L.), and indicate an active adenosine triphosphate participation during cholinergic activity.