Purification of choline acetyltransferase from the locust Schistocerca gregaria and production of serum antibodies to this enzyme.

Choline acetyltransferase (ChAT; EC 2.3.1.6) was purified from the heads of Schistocerca gregaria to a final specific activity of 1.61 mumol acetylcholine (ACh) formed min-1 mg-1 protein. The molecular mass of the enzyme as determined by gel filtration is 66,800 daltons. The final enzyme preparation showed one major band at 65,000 daltons on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, which corresponds with the native molecular mass of the enzyme, a band at 56,000 daltons, and two bands at 40,500 and 38,000 daltons. Antibodies raised against ChAT in rabbit react only with the active band on native gel after Western blotting. They strongly react with the 65,000-dalton polypeptide band on Western blots of SDS gel separation of pure preparation of enzyme and with both the 65,000- and 56,000-dalton bands after SDS gel separation of crude extract.