Fig. 5.

Enzymatic activity of ΔSP-OmAGAL2 expressed in E. coli. (A) Effect of pH on α-galactosidase activity of ΔSP-OmAGAL2. The activity was measured in 0.1 M citrate buffer (pH 3.0−6.0, dark blue) or 0.1 M phosphate buffer (pH 6.0−8.0, pale blue) at 37 °C for 30 min using p-NP-α-gal (1.0 mM) as a substrate. Values are means ±SD (n=3). (B–D) UPLC-ELSD chromatogram of purified planteose (B), authentic Suc (C), and reaction product after incubation of planteose with ΔSP-OmAGAL2 under pH 5.0 (D). Blue and red dashed lines indicate the peaks of planteose and Suc, respectively.