Fig. 2

Relative enzymatic activities of acetolactate synthase (ALS) in crude yeast cell extracts. Various ALS (ilv and als) genes were expressed in S. cerevisiae YPH499 strain (YIDB001–019). Crude protein extracts were prepared from cells grown in 5 mL SD selection medium for 48 h and used to measure relative ALS enzyme activities (see Additional file 3: Method S6). The white bar shows the relative ALS activity of the control strain harboring a mock control vector (pGK425; YIDB001) and was used for normalization. The gray bars show the relative ALS activities of yeast strains expressing the ILV2 gene (encoding the endogenous S. cerevisiae ALS; YIDB002) and the ILV2c gene (a truncated version of the ILV2 gene lacking the mitochondrial signal sequence to localize Ilv2p in the cytosol; YIDB003) as positive controls. The black bars show the relative ALS activities of yeast strains expressing various ALS genes (YIDB004–019). Ao, Aspergillus oryzae; Bs, Bacillus subtilis; Cg, Corynebacterium glutamicum; Ec, Escherichia coli; Gm, Glycine max; He, Halomonas elongata; Ll, Lactococcus lactis; Lp, Lactobacillus plantarum; Sg, Streptomyces griseus; Tf, Thermobifida fusca; Zm, Zea mays. Data are presented as the mean ± standard deviation of three independent transformants (n = 3 each)