Preparation of an antiserum using a fusion protein produced by a cDNA for rat aromatic L-amino acid decarboxylase.

Aromatic L-amino acid decarboxylase (AADC) decarboxylates L-DOPA and 5-hydroxytryptophan into dopamine and serotonin, respectively. Starting from a rat AADC cDNA clone isolated in our laboratory, we produced a beta-galactosidase-AADC fusion protein in E. coli. It was purified from inclusion bodies and injected into a rabbit. The antiserum identified AADC on a Western blot of extracts from rat organs as a unique 50 kDa band; it also strongly reacted by immunohistochemistry with dopaminergic and serotonergic neurons. This new beta-galactosidase-AADC fusion protein then constitutes a useful tool for producing AADC as an antigen free of contamination by mammalian proteins.