Glycerophosphocholine release in human erythrocytes

1H spin-echo and 31P-NMR evidence for lysophospholipse

Authors


Correspondence to P. W. Kuchel, Department of Biochemistry, The University of Sydney, Sydney, New South Wales, Australia 2006

Abstract

The direct techniques of 1H spin-echo and 31P-NMR spectroscopy made it possible to monitor the release of glyccrophosphocholine 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.

Abbreviations
GroP

sn-glycerol-3-phosphate

GroPCho

sn-glycerol-3-phosphocholine

Hc

haematocrit, i.e. blood cells/whole blood (by vol.)

lysoPtdCho

lysophosphatidylcholine

PLP A2

phospholipase A2

PtdCho

3-sn-phosphatidylcholine

PtdEtn

3-sn-phosphatidylethanolamine

RBC

red blood cells

Enzymes
 

Glycerophosphocholine phosphodiesterase (EC 3.1.4.2)

 

lecithin:cholesterol acyltransferase (EC 2.3.1.43)

 

lysophosphatidylcholine acyltransferase (EC 2.3.1.23)

 

lysophospholipase (EC 3.1.1.5)

 

phospholipase A2 (EC 3.1.1.4)

 

phospholipase D (EC 3.1.4.4)

Ancillary