Purification of T. gondii acidocalcisomes from iodixanol step gradients.

Yield values are percentages relative to the S1 fraction shown in Fig. 1.*The cytochrome c reductase activity in these fractions were below detectable levels.#Methods for determination of enzymatic activities are described under “Materials and methods” and in Rodrigues et al, 2002 [2].Purification fold was calculated from the ratio of the activity in the acidocalcisome fraction to the activity in the S1 fraction (Fig. 1).@This activity corresponds to the pyrophosphatase activity insensitive to AMDP. It is used as a cytosolic marker.AMDP, aminomethylenediphosphonate; WT, wild type cells; TgVP1-OE, T. gondii overexpressing vacuolar proton pyrophosphatase.