Walker, D.H. and Pike, L.J. (1990) Stimulation of Purified Phosphatidylinositol 4-kinase by Cobra Venom Cardiotoxin Biochimica et Biophysica Acta 1055: 295-298.

Cobra venom cardiotoxin was found to stimulate the phosphatidylinositol kinase activity present in A431 cell membranes and in detergent extracts of these membranes. Incubation of highly purified phosphatidylinositol 4-kinase from this source with cardiotoxin resulted in a 2- to 3-fold stimulation of phosphatidylinositol kinase activity. The activation of the purified phosphatidylinositol 4-kinase by cardiotoxin was time- and dose-dependent and appeared to be associated with a decrease in the K_m apparent of the enzyme for phosphatidylinositol with no change in the V_max apparent of the enzyme. The data suggest that the phosphatidylinositol 4-kinase is activated by direct interaction of the enzyme with cobra venom cardiotoxin.