M. Netopilova et al., INFLUENCE OF SANGUINARINE ON THE GABA SYNTHESIZING ENZYME GLUTAMATE-DECARBOXYLASE IN-VITRO, Die Pharmazie, 51(8), 1996, pp. 589-591
The inhibitory activity of the quaternary benzophenanthridine alkaloid
sanguinarine on rat brain glutamate decarboxylase (GAD; EC 4.1.1.15)
was studied in vitro. A value of K-i 7 . 10(-4) mol . l(-1) for sangui
narine was found. The inhibition was irreversible and increased during
the preincubation time of sanguinarine with the GAD preparation. The
results suggest that reaction of the iminium bond in the benzophenanth
ridine molecule with thiol groups of the enzyme participates in GAD in
hibition. As GAD catalyzes the rate-limiting step of GABA synthesis, i
ts inhibition by sanguinarine may contribute to its physiological acti
on in vivo.