A comparison between adenylate cyclase solubilized from normal and Rous sarcoma virus-transformed chicken embryo...

The specific activity of adenylate cyclase in membrane preparations obtained from Rous Sarcoma virus-transformed chicken embryo fibroblasts is two to four times lower than that found in untransformed membranes. Adenylate cyclase was solubilized from normal and transformed membranes in order to evaluate the influence of the membrane phase on the properties of the enzyme. Adenylate cyclase in normal and transformed membranes differed in specific activity, V for ATP, activation entropies, sensitivity to Ca2+, and stability at 37 degrees C. Solubilization with Brij 96 abolished or greatly reduced these differences. These data suggest that the differences between adenylate cyclase activities in normal and transformed chicken embryo fibroblasts are due either to differential modulation of enzyme activity by an effector which requires intact membranes for its effects, or indirect effects due to altered membrane properties.