The Purification of Acetoacyl Carrier Protein Synthase from Avocado and Identification of a Separate Acetyl CoA:ACP Transacylase Activity

Abstract

The biosynthesis of fatty acids in plants is catalysed by a type II, dissociable, fatty acid synthetase (FAS) made up of at least six catalytic polypeptides and a central, acyl carrier protein (ACP). There are three β ketoacyl-ACP synthetases (KAS): KAS 1, catalysing the initial reaction between acetyl ACP and malonyl ACP; KAS 2, catalysing the addition of acetyl ACP to the elongating fatty acid chain and the recently identified KAS 3. A further enzyme implicated in the initiation of FAS is acetyl CoA:ACP transacylase (ACAT) [3]. ACAT catalyses the formation of acetyl ACP. KAS 3, however does not utilise acetyl ACP, instead the condensation occurs between malonyl-ACP and acetyl CoA. There has recently been much discussion about the possible roles of KAS 3 and ACAT which appear to have partially overlapping functions