Glycerophosphocholine release in human erythrocytes. 1H spin-echo and 31P-NMR evidence for lysophospholipase.

The direct techniques of 1H spin-echo and 31P-NMR spectroscopy made it possible to monitor the release of glycerophosphocholine from lysophosphatidylcholine in lysates from human red blood cells. Thus, the existence of a lysophospholipase in human erythrocytes was confirmed using a new more direct method. No evidence for a phospholipase A2 activity in the haemolysates was found with the same approach; since this enzyme is present in leukocytes, the absence of activity helped verify the purity of the erythrocyte preparation. The lysophospholipase may constitute, with the earlier described glycerophosphocholine phosphodiesterase activity, a metabolic unit for the removal of haemolytic lysophosphatidylcholine which is formed in the erythrocyte membranes as well as taken up from the plasma.