A comparative analysis of the molecular characteristics of the Arabidopsis CoA pyrophosphohydrolases AtNUDX11, 15, and 15a.

Coenzyme A (CoA) is an essential, ubiquitous cofactor in all biological systems, where it acts as the major acyl group carrier in various central metabolic reactions. Although much is known about CoA biosynthesis, it is unclear how the CoA pool is regulated the various cellular compartments. It has been found that the nucleoside diphosphates linked to some moiety X (Nudix) hydrolases, AtNUDX11 and 15, have pyrophosphohydrolase activity toward CoA and its derivatives. In this study we identified two alternatively spliced variants, AtNUDX15 and 15a, produced from the AtNUDX15 gene, and carried out comparative studies of the gene regulation, the kinetic parameters, and the intracellular localization of AtNUDX11, 15, and 15a. The present findings indicate that AtNUDX11 and AtNUDX15(a) function in the hydrolysis of malonyl-CoA in cytosol and succinyl-CoA in the mitochondria, respectively, suggesting their impact not only on CoA biosynthesis but also on various CoA-related pathways such as the TCA cycle.