Certain properties of CDS4.1 and CDS5 heterologously expressed in yeast. A, Enzymic activity of CDS4.1 (white circles) and CDS5 (black circles) in dependence on CTP concentrations. B and C, Enzymic activities of CDS4.1 (B) and CDS5 (C) as a function of the concentrations of three different PA species (triangles, dioleoyl; squares, dipalmitoyl species; diamonds, species from egg lecithin).