Table 2.

Kinetic parameters of NPP1, NPP2 and NPP6

Substrates	NPP1				NPP2				NPP6
	Km (mM)	Vmax (U mg−1)a	kcat (s−1)	kcat/Km (s−1 M−1)	Km (mM)	Vmax (U mg−1)	kcat (s−1)	kcat/Km (s−1 M−1)	Km (mM)	Vmax (U mg−1)	kcat (s−1)	kcat/Km (s−1 M−1)
ADP-glucose	0.8	183	214	2.50 × 105	NQ	NQ	NQ	NQ	0.7	105	130	1.93 × 105
ADP-ribose	1.4	317	370	2.48 × 105	NQ	NQ	NQ	NQ	NT	NT	NT	NT
GDP-mannose	0.8	129	151	1.90 × 105	NQ	NQ	NQ	NQ	NT	NT	NT	NT
CDP-glucose	0.9	107	125	1.93 × 105	NQ	NQ	NQ	NQ	NT	NT	NT	NT
UDP-glucose	1.5	242	282	1.93 × 105	NQ	NQ	NQ	NQ	1.6	93	115	0.73 × 105
TDP-glucose	NTb	NT	124	2.06 × 105	NT	NT	NT	NT	1.8	65	81	0.45 × 105
ATP	2.1	356	415	2.03 × 105	NT	NT	NT	NT	NT	NT	NT	NT
ADP	4.3	385	449	1.00 × 105	1.1	68	80	0.73 × 105	0.3	68	83	2.97 × 105
APS	3	282	329	1.09 × 105	0.5	29	34	0.68 × 105	0.8	6	76	0.93 × 105
UDP	NT	NT	NT	NT	1.2	85	101	0.84 × 105	0.5	84	104	2.03 × 105
GDP	NT	NT	NT	NT	0.9	24	28	0.32 × 105	NT	NT	NT	NT
IDP	NT	NT	NT	NT	2.2	75	88	0.40 × 105	NT	NT	NT	NT
CDP	NT	NT	NT	NT	1.9	76	89	0.47 × 105	NT	NT	NT	NT
TDP	NT	NT	NT	NT	2.6	74	87	0.34 × 105	1.1	71	87	0.81 × 105
NAD+	0.8	93	109	1.33 × 105	NT	NT	NT	NT	NT	NT	NT	NT
NADP+	1.6	121	141	0.85 × 105	NT	NT	NT	NT	NT	NT	NT	NT
PPi	NT	107	125	NT	2.2	34	40	0.18 × 105	0.5	64	79	1.75 × 105
Bis-p-NPP	1.3	116	223	1.71 × 105	2.6	60	71	0.27 × 105	3.0	250	308	1.03 × 105
Hexose-P	NQc	NQ	NQ	NQ	NQ	NQ	NQ	NQ	NQ	NQ	NQ	NQ
Mononucleotide	NQ	NQ	NQ	NQ	NQ	NQ	NQ	NQ	NQ	NQ	NQ	NQ

The enzyme assay was carried out at a substrate concentration of 0.1–10 mM, at 37°C, and at optimal pH. The data give the averages of duplicate experiments.

^a U mg⁻¹, µmol min⁻¹ (mg of protein)⁻¹.

^b NT, not tested.

^c NQ, not quantifiable.