The Interaction of Human Erythrocytes with Sodium Palmitate

Abstract

The distribution, between human erythrocytes and human serum albumin, of varying quantities of palmitate ion was measured by means of C14-labeled palmitate. The conditions used were isotonic phosphate buffer-NaCl, pH 7.45, 23[degree]C. Analysis of the results in terms of a single class of binding sites on the erythrocytes indicated that there are 5.3 x 10-11 moles of binding sites per 106 erythrocytes, and that the apparent association constant for each site is 2.2 x 106. This number of sites is equivalent to 3.2 x 107 binding sites per erythrocyte. It was also shown that the binding sites are located on the erythrocyte ghosts, and that the binding reaction is independent of the metabolic activity of the cell. The results are discussed in terms of the hypothesis that the initial step in plasma unesterified fatty acid metabolism involves the transfer of unesterified fatty acids from serum albumin to receptor sites on cell surfaces.