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Fig. 5 | Annals of Microbiology

Fig. 5

From: Characterization of β-galactosidase and α-galactosidase activities from the halophilic bacterium Gracilibacillus dipsosauri

Fig. 5

Biochemical characteristics of β-galactosidase I (white circle), β-galactosidase II (white triangle) and α-galactosidase (white square) from G. dipsosauri strain DD1. Partially-purified proteins from the DEAE-Sepharose column were tested in triplicate using β-ONPG as the substrate for β-galactosidase and α-PNPG as the substrate for α-galactosidase activity, respectively. Data points show the mean + one standard deviation of each assay. Panel (a) shows Lineweaver-Burke plots of a kinetic analysis in which the concentration of the substrate was varied. Linear regression lines were fitted to each set of data points using Excel and both the equation and R2 value for each line are shown. Panel (b) shows the effects of pH on each enzyme activity using Z buffers adjusted to the pH indicated. The control activities (pH 7.0) were 143 nmol min−1 ml−1 for β-galactosidase I, 196 nmol min−1 ml−1 for β-galactosidase II, and 677 nmol min−1 ml−1 for α-galactosidasePanel (c) shows the effects of added salts (1.0 mol l−1) on the β-galactosidase I (open bars), β-galactosidase II (light bars ), and α-galactosidase (dark bars) activities. The control activities were 132 nmol min−1 ml−1 for β-galactosidase I, 163 nmol min−1 ml−1 for β-galactosidase II, and 685 nmol min−1 ml−1 for α-galactosidase. Panel (d) shows the effects of added sugars (10 mmol l−1) on the β-galactosidase I (open bars), β-galactosidase II (light bars), and α-galactosidase (dark bars) activities. The control activities were 229 nmol min−1 ml−1 for β-galactosidase I, 191 nmol min−1 ml−1 for β-galactosidase II, and 692 nmol min−1 ml−1 for α-galactosidase

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