Fig. 4.
Enzyme activity of β-galactosidase (Gal) and methionine adenosyltransferase (MAT) under the control of 8 selected PGAP library members. (A) Specific activity of Gal (white) and MAT (gray) under the control of 8 different promoters as indicated. Enzyme specific activity is given in U/mg protein in the cell lysates. Experiments were carried out in shake flask cultures for 60 h in buffered minimal glycerol (BMGY) medium. Samples for measuring enzyme activity and biomass were taken at the end of the fermentation. (B) Relative Gal activity under the control of 8 different promoters as a function of the yEGFP fluorescence controlled by the same promoter. (C) Relative MAT activity under the control of 8 different promoters as a function of the yEGFP fluorescence controlled by the same promoter. The relative enzyme activities and yEGFP fluorescence were normalized to the value obtained with the wild-type PGAP. Data represent means ± standard deviations of three independent cultivations.