TABLE 3.

NMN phosphatase activity in whole cells

Strain	Genotypea	Total phosphate released (SD)b	Release corrected for PhoN activityc
TR5958	nadB pncA	2.0 (0.12)	1.2
TT24636	nadB pncA aphA	0.9 (0.05)	0.1
TT24637	nadB pncA phoN	1.2 (0.08)	1.2
TT24638	nadB pncA aphA phoN	0.08 (0.01)	0.08
TT22855	nadB pncA pnuC*	2.0 (0.09)	1.2
TR7262	nadB pncA aphA*	4.0 (0.11)	3.2

^aComplete genotypes are shown in Table 1.

^bAssays were performed with whole cells in duplicate as described in Materials and Methods. The activity is expressed in nmol PO₄/min per 25 μl cell suspension (optical density at 600 nm, 0.6).

^cValues were corrected for the contribution of PhoN to total phosphate release, which was inferred to come from derived ribose 5-phosphate rather than NMN itself (see text). The PhoN contribution (2.0 − 1.2 = 0.8 nmol PO₄/min per 25 μl) was subtracted from the total phosphate release seen in all phoN⁺ cells.