A Key Enzyme of the NAD Salvage Pathway in Thermus thermophilus: Characterization of Nicotinamidase and the Impact of Its Gene Deletion at High Temperatures.

NAD (NAD) is a cofactor related to many cellular processes. This cofactor is known to be unstable, especially at high temperatures, where it chemically decomposes to nicotinamide and ADP-ribose. Bacteria, yeast, and higher organisms possess the salvage pathway for reconstructing NAD from these decomposition products; however, the importance of the salvage pathway for survival is not well elucidated, except for in pathogens lacking the NAD synthesis pathway.