Catalyzes the condensation of pantoate with beta-alanine in an ATP-dependent reaction via a pantoyl-adenylate intermediate. (R)-pantoate + ATP + beta-alanine = (R)-pantothenate + AMP + diphosphate + H(+) Activation requires a combination of a divalent cation, magnesium or manganese, and a monovalent cation, potassium or ammonium. Above the optimum concentration for activation, magnesium and manganese are rather inhibitory. Also activated by 2-mercaptoethanol, dithiothreitol, cysteine and glutathione. Inhibited by divalent cations (mercury, cobalt, zinc, copper, silver), chelating agents (EDTA, EGTA and o-phenanthroline), and analogs of beta-alanine (taurine, gamma-aminobutyrate, gamma-amino-beta-hydroxybutyrate). Optimum pH is 10. Stable from pH 5.0 to 11.0. Optimum temperature is 30 degrees Celsius. Stable up to 37 degrees Celsius and loses activity almost completely when incubated at 60 degrees Celsius for 10 minutes. Cofactor biosynthesis; (R)-pantothenate biosynthesis; (R)-pantothenate from (R)-pantoate and beta-alanine: step 1/1. Homodimer. The reaction proceeds by a bi uni uni bi ping pong mechanism. Belongs to the pantothenate synthetase family.