The conversion of (R)-pantoate to (R)-4′-phosphopantothenate is part of the pathway leading to biosynthesis of 4′-phosphopantetheine, an essential cofactor of coenzyme A and acyl-carrier protein. In bacteria and eukaryotes this conversion is performed by condensation with β-alanine, followed by phosphorylation (EC 188.8.131.52 and EC 184.108.40.206, respectively). In archaea the order of these two steps is reversed, and phosphorylation precedes condensation with β-alanine.
Yokooji, Y., Tomita, H., Atomi, H. and Imanaka, T. Pantoate kinase and phosphopantothenate synthetase, two novel enzymes necessary for CoA biosynthesis in the Archaea. J. Biol. Chem.284 (2009) 28137–28145. [PMID: 19666462]