Figure 3. Myr treatment lowers the rate of amino acid uptake. Uptake of radioactive amino acids was quantified after 4 h of growth of the indicated prototrophic strains (BY4741 background) in SDC medium. (A) The concentration of amino acids in the uptake assay was equal to one-fifth of the concentration in SDC medium. The mixture of 14C-labeled amino acids contained Glu (16%), branched chain amino acids (29%), Ala (13%), Asp (12.5%) and Phe (8.9%) with smaller amounts of the other amino acids. (B) Uptake of 3H-Met was performed with 12 μmol/L substrate, the Km for Mup1 transport, to evaluate activity of this high affinity transporter. (C) Uptake of 3H-Met was performed with 68 μmol/L substrate to determine if the activity of other AATs besides Mup1, with a lower affinity for Met, responded to drug treatment. (D, E). Uptake assays for 14C-glutamate and 14C-arginine were performed in medium containing 100 μmol/L substrate. Statistical significance determined by using the Student’s t-test for all data shown in this Figure and error bars are SD.