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Table 5 Kinetic parameters of Thermobacillus xylanilyticus xylanase (Tx-Xyn) and mutants for hydrolyses involving either birchwood xylan (BWX) or LVWAX

From: Engineering better biomass-degrading ability into a GH11 xylanase using a directed evolution strategy

Mutant Kinetic parametersa SRc
  BWX LVWAX  
  k cat (s-1) KMb (g/l) kcat /KMb(s-1/g/l) k cat (s-1) KMb (g/l) kcat /Kmb (s-1/g/l)  
Tx-Xyn 610.5 ± 19.6 2.54 ± 0.19 242.1 1,699.4 ± 95.9 5.10 ± 0.09 333.1 0.73
Y6H 806.1 ± 61.2 2.37 ± 0.27 340.5 2,081.6 ± 16.4 5.73 ± 0.09 363.0 0.94
S27T 742.9 ± 22.4 1.93 ± 0.15 376.5 1,936.0 ± 19.2 4.81 ± 0.04 402.5 0.94
Y111H 449.3 ± 23.2 1.54 ± 0.14 292.0 1,889.0 ± 72.9 5.01 ± 0.07 376.7 0.78
Y6H-Y111H 433.1 ± 12.5 1.91 ± 0.11 226.8 1,834.7 ± 75.4 5.33 ± 0.35 345.9 0.66
S27T-Y111H 535.8 ± 30.2 1.72 ± 0.21 311.5 1,906.1 ± 4.4 4.39 ± 0.02 434.1 0.72
Y3W 704.5 ± 29.8 2.11 ± 0.14 333.4 1,743.0 ± 26.5 5.51 ± 0.02 316.3 1.05
Y111S 758.8 ± 15.9 2.12 ± 0.04 358.6 1,755.0 ± 106.3 4.75 ± 0.14 369.4 0.97
Y111T 905.2 ± 17.2 2.35 ± 0.15 369.4 1,740.4 ± 41.8 4.81 ± 0.06 361.4 1.02
  1. aAll data presented are the result of triplicate experiments.
  2. bThe heterogeneous nature of the substrate excludes the determination of a value for KM , thus values are apparent.
  3. cRatio of the performance constants k c a t B W X / K M B W X / k c a t L V W a X / K M L V W A X for a given enzyme.