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Table 2 Relative activity of purified Gal308 with several nitrophenyl-derived chromogenic substrates and its natural substrate lactose

From: Metagenomic approach for the isolation of a thermostable β-galactosidase with high tolerance of galactose and glucose from soil samples of Turpan Basin

Substrate Activitya(%)
o-Nitrophenyl-β-D-galactopyranoside (ONPG) 100
p-Nitrophenyl-β-D-galactopyranoside (pNPG) <1
o-Nitrophenyl-β-D-fucopyranoside <1
p-Nitrophenyl-β-D-mannoside 3.5±0.3
o-Nitrophenyl-β-D-glucoside <1
p-Nitrophenyl-β-D-xyloside 5.7±0.2
p-Nitrophenyl-β-D-cellobioside <1
p-Nitrophenyl-β-D-lactoside 7.8±0.3
p-Nitrophenyl-α-D-galactoside <1
Lactose 25.7±1.8
  1. a The values are relative to the 100% value observed with ONPG (185 U/mg).
  2. Hydrolysis of lactose in milk by Gal308.