Look at lane 3. Click on the band, which represents NON – SPECIFIC labeling (i.e. the band whose presence is not due to an interaction between the primary antibodies and a proton pump).

Legend Lanes 1, 8  Size marker (kilo Daltons) Lane  2      Purified proton pump Lane  3      Lysate of the whole Paramecium Lane  4      Lysate of the Parameciun food vacuole collected 0.5 min after feeding. Lane  5      Lysate of the Parameciun food vacuole collected 5 min after feeding. Lane  6      Lysate of the Parameciun food vacuole collected 10 min after feeding. Lane  7      Lysate of the whole Paramecium reacted only with the secondary antibody.