FIG. 6.

Distribution of PPase activity from procyclic and bloodstream trypomastigotes on Percoll gradients. PPase is concentrated in a distinct dense fraction. V-H⁺-PPase activity, measured by proton uptake or phosphate release, was compared with the distribution of ATPase activity and the established organelle markers isocitrate dehydrogenase (mitochondria), α-mannosidase (lysosome), hexokinase (glycosome), and α-glucosidase (plasma membrane). Charts show mean activity ± SE (as a percentage of the total recovered activity) from three to seven independent experiments. Light gray bars represent procyclics, and dark gray bars represent bloodstream trypomastigotes. Density was measured in a single experiment by using Percoll density marker beads. Protein distribution in the different fractions of procyclic and bloodstream trypomastigotes is indicated by closed and open circles, respectively.