Chapter 18.10, Problem 21P

Interpretation Introduction

Interpretation:

The number of moles of acetyl-CoA which should be converted to malonyl-CoA in order to synthesize 1 mole of arachidic acid has to be determined.

Concept introduction:

For the synthesis of arachidic acid, in first step acetyl thioester and malonyl thioester undergoes Claisen condensation.  The product of Claisen condensation undergoes reduction, dehydration and a second reduction to form a four-carbon thioester.

The four carbon thioester combines with another molecule of malonyl thioester and undergoes Claisen condensation, reduction, dehydration and a second reduction to form a six carbon thioester. The reaction can proceed to form a fatty acid of an even number of carbon atoms and repetition of sequence adds two carbon.