cl17275

Phosphoribosyltransferase (PRTase) type II; This family contains two enzymes that play an important role in NAD production by either allowing quinolinic acid (QA) , quinolinate phosphoribosyl transferase (QAPRTase), or nicotinic acid (NA), nicotinate phosphoribosyltransferase (NAPRTase), to be used in the synthesis of NAD. QAPRTase catalyses the reaction of quinolinic acid (QA) with 5-phosphoribosyl-1-pyrophosphate (PRPP) in the presence of Mg2+ to produce nicotinic acid mononucleotide (NAMN), pyrophosphate and carbon dioxide, an important step in the de novo synthesis of NAD. NAPRTase catalyses a similar reaction leading to NAMN and pyrophosphate, using nicotinic acid an PPRP as substrates, used in the NAD salvage pathway.