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Table 2 Biochemical properties of TKT P and TKT C

From: Characterization of two transketolases encoded on the chromosome and the plasmid pBM19 of the facultative ribulose monophosphate cycle methylotroph Bacillus methanolicus

Parameter TKTC TKTP
Molecular weight 73 kDa 73 kDa
280 kDa (tetramer) 280 kDa (tetramer)
Optimal activity conditions: 50 mM Tris–HCl, pH 7.5, 2 mM Mn2+, 2 μM THDP, 55°C 50 mM Tris–HCl, pH7.7, 5 mM Mn2+, 1 μM THDP, 55°C
Optimal pH 7.2-7.4 7.2-7.4
Optimal temperature 62°C 62°C
Temperature stability < 60°C < 60°C
Kinetics   
X5P KM     0.15 ± 0.01 mM     0.23 ± 0.01 mM
Vmax   34 ± 1 U/mg   45 ± 28 U/mg
kcat   40 s-1   54 s-1
kcat/KM 264 s–1 mM–1 231 s–1 mM–1
R5P KM     0.12 ± 0.01 mM     0.25 ± 0.01 mM
Vmax   11 ± 1 U/mg   18 ± 1 U/mg
kcat   13 s-1   21 s-1
kcat/KM 109 s–1 mM–1   84 s–1 mM–1
GAP KM     0.92 ± 0.03 mM     0.67 ± 0.01 mM
Vmax   85 ± 3 U/mg   42 ± 1 U/mg
kcat   99 s-1   48 s-1
kcat/KM 108 s–1 mM–1   71 s–1 mM–1
F6P KM     0.72 ± 0.11 mM     0.25 ± 0.01 mM
  Vmax   71 ± 11 U/mg   96 ± 5 U/mg
  kcat   82 s-1 112 s-1
  kcat/KM 115 s–1 mM–1 448 s–1 mM–1
  1. Values for KM (mM), Vmax (U/mg), and catalytic efficiency (kcat/KM = s-1 mM-1) were determined for two independent protein purifications and mean values and arithmetric deviations from the mean are given.