Question

Describe the process of activation of acetyl-CoA for use in the synthesis of fatty acids and the role of the acyl carrier protein?

Answer 1

The fatty acid synthesis occurs in the cytosol. The acteyl CoA is produced in the mitochondrion during the gylcolysis, and to transport it to cytosol as cytosolic acetyl CoA , the citrate ( that is obtained by condenstaion of acetyl CoA and oxaloacetate)form the citric acid cycle, is removed and carried accross the inner mitochondrial membrane into the cytosol. There, the citrate is cleaved by ATP citrate lyase to form acetyl CoA and oxaloacetate. This acetyl CoA is actually the cytosolic acetyl CoA which is later carboxylated by acetyl CoA carboxylase, to form malonyl CoA . Malonyl CoA formation is the first step of fatty acid synthesis. Hence, it can be said that acetyl CoA ia activated.

The role of acyl protein is to carry acyl intermediates during fatty acid synthesis. The acyl proteins are universal. This protein is expressed in inactive apo form.