FIG. 3.

Effects of monoiodoacetate, EDTA, and divalent cations on PghP activity. Reactions proceeded at 37°C for 60 min in PghP assay mixture (see Materials and Methods) containing 50 mM Tris-HCl (pH 7.5) instead of 50 mM sodium phosphate (pH 7.5), and reaction products were analyzed using agarose gel electrophoresis. Lane 1, no enzyme (control). Lanes 2 through 8 contained 45 ng of purified PghP/ml plus the following: lane 2, no further addition; lane 3, 1 mM EDTA; lane 4, 1 mM EDTA + 5 mM CaCl₂; lane 5, 1 mM EDTA + 5 mM MgCl₂; lane 6, 1 mM EDTA + 5 mM MnCl₂, lane 7, 1 mM EDTA + 5 mM ZnCl₂; lane 8, 1 mM monoiodoacetate. Reaction mixtures for lanes 4 to 7 were incubated for 5 min before adding chlorides.