The effect of acidic lipids on the activity of bovine milk galactosyltransferase in vesicles of different phosphatidylethanolamines.

Bovine milk galactosyltransferase was incorporated into vesicles prepared from different phosphatidylethanolamines which varied widely in both their gel-liquid crystalline and their lamellar-hexagonal phase transition temperatures. Although all phosphatidylethanolamines stimulated the activity of the enzyme the extent of stimulation varied. Acidic lipids phosphatidylserine and phosphatidic acid inhibited the activity of the enzyme incorporated into all of the phosphatidylethanolamines except when the enzyme was in soya PE in which the acidic lipids had no effect.