Thread by @CharlesMBrenner

Did you know that NAD, NMN and NR were described in the 1940s as factor V, an essential growth factor to grow Haemophilus influenza? H influenza is a flu-causing bacterium that only a few microbiologists ever wanted to grow. NR worked better than NMN and NAD because /1

Phosphorylated compounds can't get into cells. H influenza needs NR because it doesn't have the genes to make NAD from amino acids, nicotinamide or nicotinic acid. There was no market for NR because who wants to grow H influenza? /2

In 2004, I was working on glutamine-dependent NAD synthetase in yeast. This enzyme performs the final step in making NAD from tryptophan, nicotinamide and nicotinic acid (all the then-known NAD precursors in eukaryotic cells). /3

I questioned whether there was another way to make NAD in yeast & showed that NR is a precursor--this showed the vitamin activity of NR. Pawel Bieganowski & I then found the yeast NRK1 enzyme plus the mouse and human NR kinase genes, establishing the identity of the NR pathway./4

These are important genes that get turned up when NAD is under attack. The @dartmouth patents on uses of NR as a food/nutritional supplement and a potential drug came of this discovery doi.org/10.1016/S0092-… #metabolism #NAD #NR

Discovered to be a vitamin as opposed to a growth factor for Haemophilus influenza