Fractions (total protein) Manometric method μl CO2/min/ mg protein Fluorimetric method ΔF /min/mg protein Purity fold Brain Supernatant 0.05 (0.01) 0.23 (0.01) - DEAD-cellulose eluate 0.25 (0.11) 1.36 (0.09) 5.1 Hydroxyapatate eluate 2.24 (0.47) 10.51 (0.78) 45.5 Gel filtration eluate 7.06 (1.92) 32.50 (2.04) 140.5

Table 1: Specific activity of rat brain glutamate decarboxylase in different steps of the purification. The rate of CO2 production and the changes of fluorescence intensities in each step of purification were measured by manometric and fluorimetric methods respectively. The results are mean of 6 separate experiments with SD in round brackets. In each experiment 5 forebrains were processed as described in the Method section.