FIG. 2.

Zero-trans lactose uptake rates of the recombinant S. cerevisiae strains T1 (gray columns) and T1-E (white columns) and the K. lactis strain CBS2359 (striped columns). The three yeasts were grown at 30°C, and the rates were measured by transport assays using ¹⁴C-labeled lactose at 20°C with 2 mM lactose and at 30°C with 2 and 20 mM lactose, as indicated. K. lactis was also grown at 18°C and assayed at 18°C with 2 and 20 mM lactose. Error bars are the standard deviations of 2 to 8 determinations with independently grown yeast suspensions.