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Table 5 Enzyme kinetics for the selected substrates

From: Activation of LacZ gene in Escherichia coli DH5α via α-complementation mechanism for β-galactosidase production and its biochemical characterizations

Substrate

Vmax (U/mg/min)

Km (mM)

Kcat

(S−1)

Kcat/Km

(1/mM S)

oNPG

14.2

1.4

312

219.7

Lactose

6.4

12.92

93

7.1

  1. Enzyme activity for the selected substrates was assessed under standard conditions using 0.5–25 mM of O-nitrophenyl b-d-galactopyranoside or 20–360 mM of lactose in 50 mM sodium phosphate buffer (pH 7.8) at 40 °C for 10 min. For lactose-hydrolyzing activity, glucose oxidase was used to determine the specific activity. The Km and Vmax values were calculated by a Lineweaver-Burk plot