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Table 2 Purification steps of LacA-WT and mutants from JM109(DE3)

From: Effect of mutations to amino acid A301 and F361 in thermostability and catalytic activity of the β-galactosidase from Bacillus subtilis VTCC-DVN-12-01

Mutant LacA

Steps of purification

Total activity (U)

Total protein (mg)

Specific activity (U/mg)

Purification factor

Yield (%)

WT

Crude β-galactosidase

5.13

9.04

0.57

1.0

100

Probond™resin

4.12

1.66

2.48

4.53

80.49

E62V

Crude β-galactosidase

4.53

8.18

0.55

1.0

100

Probond™resin

3.81

1.59

2.39

4.35

84.1

R77W

Crude β-galactosidase

5.02

9.25

0.54

1.0

100

Probond™resin

3.56

1.39

2.56

4.74

71

A191V

Crude β-galactosidase

4.32

8.72

0.50

1.0

100

Probond™resin

3.54

1.42

2.49

4.98

81.94

A301V

Crude β-galactosidase

1.15

8.66

0.13

1.0

100

Probond™resin

0.89

1.51

0.59

4.54

77.1

F361Y

Crude β-galactosidase

2.06

9.11

0.24

1.0

100

Probond™resin

1.72

1.55

1.11

4.63

83.5

A524T

Crude β-galactosidase

5.11

8.25

0.62

1.0

100

Probond™resin

4.1

1.62

2.53

4.08

80.23

  1. Wild-type and mutants of LacA were purified to homogeneityby affinity chromatography Ni2+ ProBond™ resin. The relative activity of β-galactosidase was determined in 100 mM buffer Z (pH 7.0) at 55 °C with substrate oNPG (4 mg/ml)