Table 2

Catalytic constants and substrate specificities of purified X. polymorpha GH78

SubstrateSp act (U/mg)Km (μM)kcat (s−1)kcat/Km (s−1 M−1)
p-Nitrophenyl α-l-rhamnopyranoside24.4a97132.93.4 × 104
p-Nitrophenyl α-l-arabinofuranoside1.5NDbNDND
Naringine1.2NDNDND
p-Nitrophenyl β-d-glucopyranoside0.1NDNDND
p-Nitrophenyl β-d-cellobioside0.07NDNDND
Methyl ferulate7.3a809.31.2 × 105
Methyl p-coumarate4.1a216.22.9 × 105
Methyl sinapate2.8a1033.73.6 × 104
Ethyl ferulate2.1a942.62.7 × 104
Methyl caffeate0.92a1511.49.3 × 103
Veratric acid ethyl ester0.01a780.11.3 × 103
Veratric acid methyl ester0.01a620.11.6 × 103
Methyl-6-O-sinapoyl glucopyranoside1.2NDNDND
Methyl-6-O-feruloyl glucopyranoside2.2NDNDND
Chlorogenic acid0.3NDNDND
p-Nitrophenyl acetate0.09NDNDND
Dibenzoyl tartrate0NDNDND
  • a Calculated as Vmax/protein amount.

  • b ND, not determined.