Lamprey brain contains globular and asymmetric forms of acetylcholinesterase.
To obtain more information about the evolution of acetylcholinesterase in the vertebrates, we studied the cholinesterase activity from the brain of the lamprey Petromyzon marinus. We found that the enzyme is true acetylcholinesterase and that 98% of it is present in the G(4) globular form. Only 1% of the enzyme was found distributed among the asymmetric forms A(4), A(8) and A(12); an additional 1% of the activity could not be extracted from the brain. The identity of the asymmetric forms was confirmed by collagenase digestion. These data demonstrate that asymmetric acetylcholinesterase is present in the CNS of organisms representing all classes of vertebrates. However, our results are inconsistent with an evolutionary trend that has been observed for vertebrate brain acetylcholinesterase.
Pezzmenti
L
L
Department of Biology, Birmingham-Southern College, Birmingham, AL 35254, U.S.A.
Nickson
H C
HC
Bradley
R J
RJ