-!- The enzyme, which is involved in pyridine nucleotide recycling, can form beta-nicotinate D-ribonucleotide and diphosphate from nicotinate and 5-phospho-alpha-D-ribose 1-diphosphate (PRPP) in the absence of ATP. -!- However, when ATP is available the enzyme is phosphorylated resulting in a much lower K(m) for nicotinate. -!- The phospho-enzyme is hydrolyzed during the transferase reaction, regenerating the low affinity form. -!- The presence of ATP shifts the products/substrates equilibrium from 0.67 to 1100. -!- Formerly EC 2.4.2.11.