Glutamate decarboxylase (GAD;EC 4.1.1.15) is the key enzyme responsible for the synthesis of the major inhibitory neurotransmitter γ-amino butyric acid (GABA). GAD has been reported to be present in mammalian brain, plants, bacteria, and fungi. In this study, we purified GAD from Monascus purpureus CCRC 31615 and determined its biochemical characteristics. The cultivation was conducted at 30