Purification of chlorpromazine-sensitive GTPase from rat cerebral cortex.

The chlorpromazine-sensitive GTPase from the cell membrane of rat cerebral cortex was purified to homogenity by using DEAE Bio-Gel A agarose, hydroxyapatite and heparin agarose chromatography. The purified chlorpromazine-sensitive GTPase was purified 370-fold to obtain a final specific activity of 40 mumol GTP hydrolyzed2min/mg protein. The purified enzyme was inhibited by chlorpromazine but not by compound 48/80. Magnesium was required for its activity instead of calcium. The purified enzyme had an apparent pH optimum of 8.0, and molecular weight was estimated to be 58,000.