TABLE 3.

Biochemical characterization of enzymes in NAD metbolism of Synechocystis sp. strain PCC 6803

Locus tag	Functional role	Abbreviation	Protein sample	kDae	Enzymatic activity (U/mg)f			Source or reference
					Substrate 1	Substrate 2	Ratio
					NaMN	NMN
slr0787	Nicotinamide mononucleotide adenylyltransferase	NMNAT	Recombinant, 3-step purification	39	Not reported	3.4	∼1/20	50a
sll1916	Nicotinate mononucleotide adenylyltransferase	NaMNAT	Recombinant, 2-step purification	25	1.0	<0.01	>100/1	This studyb
					Gln	NH3
slr1691	NAD synthetase	NADS	Recombinant, 2-step purification	63	0.03	0.08	∼1/2.5	This studyc
					Nam	NA
slr0788	Nicotinamide phosphoribosyltransferase	NMPRT	Recombinant, 1-step purification	54	0.5	0.003	>150/1	This studyd

^aNMNAT activity determined at 0.2 mM NMN, 0.2 mM ATP, pH 8.2; details of NaMNAT activity were not reported.

^bActivity at 1 mM NMN or NaMN with 2 mM ATP, pH 7.5.

^cActivity at 5 mM l-glutamine or 2 mM NH₄Cl with 1 mM NaAD, 2 mM ATP, pH 7.5.

^dActivity at 0.2 mM nicotinamide or nicotinic acid with 1 mM PRPP, pH 7.5.

^eAs determined by SDS-PAGE.

^fNA, nicotinic acid; Nam, nicotinamide.