ACTIVE-RAT AROMATIC-L AMINO-ACID DECARBOXYLASE AS A FUSION PROTEIN INESCHERICHIA-COLI

The DNA sequence encoding rat aromatic-L-amino acid decarboxylase (AAD C) was inserted into the Escherichia coli (E. coil) expression vector pMAL-c2. This clone produced a fusion protein able to catalyze the con version of L-DOPA to dopamine. After purification and treatment of the fusion protein by factor Xa (FXa), an enzymatically active form of th e enzyme resistant to FXa was isolated It showed kinetic constants, V- max, K-m, and enzymatic properties very similar to those obtained prev iously for the mammalian enzyme. This method for obtaining active AADC appears to be useful for initiating the study of the catalytic activi ty of this protein because it permitted the rapid isolation and the st abilization of an active form of the enzyme.