Compartmentalization of Two Forms of Acetyl-CoA Carboxylase and Plant Tolerance towards Herbicides

Abstract

Acetyl-CoA carboxylase (ACCase) catalyzes the synthesis of malonyl-CoA, the first intermediate in fatty acid synthesis. There are two forms of ACCase: a prokaryote form consisting of three protein components, biotin carboxylase, carboxyltransferase, and biotin carboxylase carrier protein, and a eukaryote form consisting of three functional domains on a single polypeptide. About 20 years ago, Kannangara and Stumpf reported the existence of the prokaryote form in spinach chloroplasts [1], the major site of fatty acid synthesis, but this finding has been dismissed because the prokaryote form has not yet been purified and the purified ACCases from various plants are all eukaryote form consisting of a subunit size of about 200 kDa, like that of the mammal enzyme.