TABLE 3.

Effects of transferrins on ATP-driven proton translocation and ATPase activity of L. lactis^a

Protein	Concn (μM, unless stated otherwise)	Final ACMA fluorescence (% of initial fluorescence)	ATPase activity (%)
Control		32 ± 0.7	8.8 ± 0.6 (100)
DCCD	0.5 mM	64 ± 0.5	2.3 ± 0.3* (26)
Lactoferrin	10	56 ± 0.8	2.1 ± 0.9* (24)
	20	86 ± 0.4	2.4 ± 0.5* (27)
	20b	77 ± 0.7	3.1 ± 0.8* (35)
	30	ND	2.2 ± 1.5* (25)
Transferrin	10	37 ± 0.9	8.3 ± 0.9 (94)
	20	ND	8.2 ± 0.7 (93)
	20b	ND	8.1 ± 0.2 (92)
	30	39 ± 0.2	8.7 ± 1.2 (99)

^aATPase activity is reported as μmol P_i min⁻¹ (mg protein)⁻¹ at 30°C. ND, not determined. Values are means ± SD for at least three experiments. *, P < 0.05.

^bIron-saturated protein.