Evidence of the presence of GTPase inhibiting proteins for a low Mr GTP-binding protein, ram p25, in rat spleen nad pheochromocytoma PC12 cells

Abstract 1. 1. GTPase inhibiting activity for a low M r GTP-binding protein, ram p25, was detected in the cytosolic fractions of rat species and PC12 cells. 2. 2. The inhibitors were heat-labile and trypsin-sensitive, indicating that they were of proteinous nature. 3. 3. The molecular mass of the inhibition in the spleen appeared to be about 65 kDa on the elution profile from the gel filtration column.