Mechanism — enzyme
NRK1 / NRK2
The kinases that phosphorylate NR into NMN.
Nicotinamide riboside kinase 1 and 2 phosphorylate NR to NMN — the dedicated entry point for NR into the NAD+ pathway. NRK2 is induced in skeletal muscle under exercise stress, one reason NR's effects are enriched in muscle tissue.