Fatty acid biosynthesis in human erythrocytes: evidence in mature erythrocytes for an incomplete long chain fatty acid synthesizing system.

Abstract

Long chain fatty-acid synthesis from acetate was studied in cell-free preparations of human erythrocytes. The pathway may be the same as in the other mammalian systems studied. Malonyl-coenzyme-A is a key intermediate. Enzyme systems with the characteristics of palmltate synthetase and acetyl-coenzyme-A synthetase are similar to those of other mammalian tissues. However, no acetyl-coenzyme-A carboxylase activity was demonstrated, explaining the inability of mature erythrocytes to synthesize long chain fatty-acids from acetate. This finding indicates that this enzyme is important in the regulation of fatty-acid biosynthesis. Fatty-acid biosynthesis may occur by the so-called malonyl-coenzyme-A pathway at an early stage of red cell development, and the loss of this synthetic activity may be due to the loss with maturity of the enzyme, acetyl-CoA carboxylase.