Fig. 7.

Functional characterization of poplar CAT11 by heterologus expression in a yeast mutant strain. (A) Yeast strain JA248 was transformed with the yeast expression vector pYES2 or pYES2 harbouring the coding sequence of Pt-CAT11. Growth was assayed on N-free medium containing 20 g L⁻¹ Gal and either 0·5, 1, 2 or 5 mm l-glutamine as sole N source. Pictures were taken after 2 d of growth at 30 °C and are representative of three replicates. (B) Concentration-dependent kinetics of [³H]glutamine uptake by yeast strain JA248 expressing Pt-CAT11. The Michaelis–Menten constant for glutamine is 690 µm. Values are expressed as the mean ± s.e. of three replicate experiments. (C) Lineweaver–Burk representation of [³H]glutamine uptake by yeast strain JA248 expressing Pt-CAT11. Values are expressed as the mean ± s.e. of three replicate experiments.