Solubilisation de l'acétylcholinestérase des organes électriques de gymnote.

Further evidence is presented in this paper concerning the occurrence of three different molecular species of acetyleholinesterase in the electric eel's electric organ. These species, A, C, and D, differ in their sedimentation coefficients (8.5 S, 14.2 S, and 18.4 S, respectively). We show that the whole of the tissue acetyleholinesterase activity can be solubilized by repeated homogenisation, in the form of A, C, and D. Homogenisations under different conditions of ionic strength, or after prolonged autolysis yield closely similar results: the ratios of A, C, and D are remarkably constant. Moreover ammonium sulfate precipitation does not affect these species. This raises the question of their relationship and significance. All three species are recognized by antibodies obtained from rabbit immured against the purified enzyme. We have also studied the solubilization of acetylcholinesterase by trypsin in electric tissue slices. This is very effective and directly yields species B. This species, which is homogeneous in sedimentation, but might contain a variety of slightly different protein molecules, can also be obtained by partial tryptic digestion of A, C, and D, The sedimentation coefficient of species B is very close to that of purified acetylcholinesterase and we have previously suggested that the two kinds of molecules may be similar. Even though this is probably correct, we have been able to detect a significant difference (0.8 S unit) in the sedimentation coefficients. [ABSTRACT FROM AUTHOR]