The effect of phospholipid bilayers on AMP-deaminase from rat tissues.

The ATP-activated adenylate deaminase (EC 3.5.4.6) from the rat heart, kidney, spleen, liver and brain showed a mixed-type allosteric activation under the influence of phosphatidylcholine-containing liposomes, but no effect was observed on the non-activated enzyme isolated from all these tissues but the brain. The brain enzyme was activated by the liposomes also in the absence of ATP. No effect of the phosphatidylcholine-containing liposomes could be shown on the adenylate deaminase isolated from skeletal muscle and red blood cells. The phosphatidate-containing liposomes exerted an inhibitory effect on the enzyme isolated from the heart, kidney and brain, being without effect on the enzyme from skeletal muscle.