TABLE 2.

Alkaline phosphatase activities of the TnphoA mutants of B. avium

Strain	Fe availability (sp act)a		Fold inductionb
	Fe replete	Fe limited
4169	0.018 ± 0.001	0.014 ± 0.001	0.8
Pho-6	0.004 ± 0.005	0.129 ± 0.042	32.3
Pho-20	0.033 ± 0.021	0.217 ± 0.045	6.6

^a

Values are the results from three replicate cultures of each strain. All values are means ± SD. Specific activities (41) are reported as micromoles of NPP hydrolyzed per minute per OD₆₀₀ unit by the formula

Fe-replete results are from cells grown in BHI supplemented with 36 μM FeSO₄, and Fe-limited results are from cells grown in BHI supplemented with 100 μM EDDA. 

^bActivity during Fe-limited culture/activity during Fe-replete culture.