Enzymatic synthesis of high-titer nicotinamide mononucleotide with a new nicotinamide riboside kinase and an efficient ATP regeneration system

Bioresources and Bioprocessing

Table 1 Comparison of nicotinamide riboside kinases (NRKs) from different sources

Entry	NRK	Specific activity (U·mg^–1)	K_{M, ATP} (μM)	K_{M, NR} (μM)
1	Human NRK1	0.275 ± 0.177 ^a	4.8 ± 0.3 ^b	3.4 ± 0.5 ^b
2	Human NRK2	2.32 ± 0.20 ^a	250 ± 12 ^b	46 ± 8 ^b
3	Sc-NRK1	0.535 ± 0.600 ^a	NA	NA
4	Klm-NRK	7.90 ± 0.42 ^c	70 ± 6 ^c	45 ± 11 ^c

NA not available, Sc Saccharomyces cerevisiae, Klm Kluyveromyces marxianus
^a Bieganowski and Brenner, 2004
^bDölle and Ziegler, 2009
^cThis work