?
Nicotinate phosphoribosyltransferase (NAPRTase), related to PncB. 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. This subgroup is present in bacteria, archea and funghi.