Figure 7.
Secretion of invertase in ergΔ mutant cells. Invertase activities were assayed in wild-type (RH1800; A), sec18 (RH1737; A), erg2Δ (RH2897; B), erg6Δ (RH3622; C), and erg2Δerg6Δ (RH3617; D) cells. Internal invertase activity (i) was calculated from the difference between the total invertase activity (cell lysate) and the surface invertase activity (whole cell; e) at each time point. Internal and external invertase activities were expressed as micromoles of glucose formed per A600 units of cells per min and plotted as a function of time after invertase induction. Open symbols, extracellular invertase activities (e); closed symbols, intracellular invertase activities (i); O.D., optical density.