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A new multifunctional protein kinase, which normally exists as an inactive form in the soluble fraction in mammalian tissues, attaches to membranes to exhibit full enzymatic activity. A low concentration of Ca2+ is absolutely necessary for this activation. This process is reversible. cAMP shows no effect. The active factors in membranes are phosphatidylinositol, phosphatidylserine, phosphatidic acid, diphosphatidylglycerol, and phosphatidylethanolamine in that order. Phosphatidylcholine and sphingomyelin are far less effective. Cytoplasmic as well as other membrane fractions from various tissues are active in supporting the enzymatic activity. A possible role of this Ca2+ and phospholipid-activated protein kinase system in transmembrane control is proposed.

Experimental data for the intrinsic diffusion coefficients 9 of methyl acetate, ethyl acetate, n-propyl acetate, and n-butyl acetate in polymethyl acrylate (P.M.A.) have been obtained as functions of penetrant concentration over a range of temperatures well above the glass transition point of pure P.M.A. For the four penetrants studied, plots of log 9 against ZQ are linear over the range of v1 at high temperatures and show downward curvature at low temperatures, where 7.11 is the volume fraction of penetrant. The apparent activation energies for diffusion, calculated from temperature dependence data for 9 at zero concentration, are approximately the same for all acetates and decrease continuously with increasing temperature. When compared at the same temperatures, these energies are smaller by a constant factor than the apparent activation energies for the viscous flow of pure P.M.A. Based on an equation for the molar friction coefficient of the penetrant, which is similar in form to the Doolittle viscosity equation, a theory is developed for temperature and concentration dependences of 9 for organic vapour into rubbery polymeric solids. Tests of it are made with the data from the present study as well as those from some previous works. In all cases examined, fairly good agreement between experimental data and predicted relations is obtained.