Table 1.

Intracellular NAD(H) levels of E. coli DH5α cells ^a harboring NTT4 expression and corresponding empty plasmids

Plasmid	Promoter	Cellular NAD(H) level (mM) b		Increment
		Empty vector	NTT4 expression
pET15k	T7	1.72 ± 0.03	1.85 ± 0.01	7.9%
pBCTC	gap P1	1.96 ± 0.00	2.13 ± 0.01	8.3%
pBCTD	gntT105 P	1.86 ± 0.05	4.47 ± 0.14	141.0%

^aCells were cultivated at 37°C for 12 h in LB media containing 0.2 mM NAD⁺, collected by centrifugation and washed twice with PBS buffer.

^bAll data represent the averages ± SDs for three independent samples.