Incorporation of orthophosphate-³²P into erythrocyte phospholipids in normal subjects and in patients with hereditary spherocytosis

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Abstract

The in vitro incorporation of inorganic 32P into erythrocyte phospholipids has been studied in normal subjects and in splenectomized patients with hereditary spherocytosis (HS). Phosphatidic acid (PA) was the only lipid measurably labeled in both kinds of cells. The actual turnover rate of PA phosphate was determined by simultaneously isolating inorganic phosphate (Pi) and adenosine triphosphate (ATP) and determining their specific activities. This turnover is very small: 1.3 μmoles P/liter of erythrocytes per hr in normal cells and 4.0 μmoles P in HS erythrocytes when either ATP or cellular Pi is considered the immediate precursor. This value represents less than 0.1% of the total membrane lipid phosphate. Incorporation of added 32Pi into the other phosphatides, including phosphatidyl serine, was essentially zero in both kinds of cells.

Authors

Claude F. Reed