Nicotinate phosphoribosyltransferase (NAPRTase) family. Nicotinate phosphoribosyltransferase catalyses the formation of NAMN and PPi from 5-phosphoribosy -1-pyrophosphate (PRPP) and nicotinic acid, this is the first, and also rate limiting, reaction in the NAD salvage synthesis. This salvage pathway serves to recycle NAD degradation products.