A unique phospholipid organization in bovine erythrocyte membranes.

FLORIN-CHRISTENSEN, J.; SUAREZ, C.; JACOBSEN FLORIN-CHRISTENSEN, M.; WAINSZELBAUM, M.; BROWN, W.C.; MC ELWAIN, T.; PALMER, G.

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA

NATL ACAD SCIENCES

Año: 2001 vol. 98 p. 7736 - 7741

0027-8424

Ruminant erythrocytes are remarkable for their choline-phospholipid anomalies; namely, low or absent phosphatidylcholine (PC) along with high sphingomyelin levels. Here, we report another anomaly in bovine erythrocytes that affects aminophospholipids: phosphatidylethanolamine (PE) shows an extreme asymmetry, with only 2% of the total present in the outer leaflet. Furthermore, we found that phospholipase A(2), an enzyme located on the external surface of the erythrocytes, shows higher activity against PC than against PE. In addition, we observed that acylation of PE is by far the most important biosynthetic event in this system. We propose that deacylation of PE and PC by phospholipase A(2) to generate lysocompounds, followed by selective reacylation of lyso-PE in the inner leaflet, can account for the compositional and architectural peculiarities of bovine erythrocyte membranes.