Figure 9.

Kinase actvities in heavy membranes are augmented by detergents but not by membrane pore-forming agents or sonication. Aliquots of light and heavy membranes containing 5 μg of total proteins were assayed for total phosphotransferase activity alone or in the presence of 0.1% TX-100, 6 mM OTG, 0.1% saponin (Sap), 100 U/ml SLO, or 10 U/ml α-toxin (a-Tox). Another set of aliquots was sonicated to disrupt the membrane vesicles before initiating the kinase reaction. Phosphorylated membrane proteins separated by SDS-PAGE were revealed by autoradiography after overnight exposure.