Journal of Lipid Research, Vol. 12, 139-142, March 1971
Copyright © 1971 by Lipid Research, Inc.

The apparent transfer of fatty acid from phosphatidylcholine to phosphatidylethanolamine in human erythrocytes

Stephen B. Shohet

Division of Hematology, The Children's Hospital Medical Center, and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115

In previous studies an apparent transfer of ¹⁴C-labeled fatty acid from phosphatidylcholine to phosphatidylethanolamine was observed in prelabeled human erythrocytes reincubated in fresh serum. These data could have been explained by direct fatty acid transfer from phosphatidylcholine to phosphatidylethanolamine or by an apparent transfer simulated by either demethylation of labeled phosphatidylcholine to phosphatidylethanolamine or base-exchange of phosphatidylcholine with ethanolamine.

To explore these possibilities, RBC containing phosphatidylcholine doubly labeled with palmitic acid-9,10-³H and with choline-1,2-¹⁴C were prepared. Upon reincubation in fresh serum, incorporation of ³H (fatty acid) into phosphatidylethanolamine was observed without incorporation of ¹⁴C (choline). In similar experiments in which RBC labeled with ³H-labeled fatty acid alone were used, ¹⁴C-ethanolamine added to the incubation was not incorporated into the isolated phosphatidylethanolamine which again showed incorporation of the fatty acid-³H.

The data indicate that direct transfer of fatty acid from phosphatidylcholine to phosphatidylethanolamine can occur in human erythrocytes incubated in fresh serum.

Supplementary key words palmitic acid

Submitted on July 2, 1970
Accepted on October 28, 1970

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