earticle

영어

Glutamate decarboxylase (GAD) is an enzyme that catalyzes the decarboxylation of L-glutamate to γ-aminobutyrate (GABA). This reaction is of interest for its application in production of GABA as the source for manufacturing nylon-4, a biodegradable polymer. The E.coli GAD was only active under acidic environments, which severely limited the scope of the reaction. GAD undergoes a drastic conformational change in a pH-dependent manner, which eventually shuts down its activity at neutral pH. Upon the structural studies, Glu89 was shown to be one of the residues of which side chains adopt different positions in active and inactive forms of GAD. Therefore, site-directed mutagenesis of this residue was performed and the consequences were evaluated to confirm any contribution of this to the inactivation process of GAD