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Table 1 Specific activity of wt-Trpase and its mutants at 25°C and after cooling to 2°C in Tricine -KCl buffer, pH = 7.5.

From: Conformational changes and loose packing promote E. coli Tryptophanase cold lability

Trpase Specific activity
25°C
(Units/mg)
2°C
wt 45.7 ± 2.5 29.7 ± 1.7
W330F 42.8 ± 3.2 5.0 ± 1.4
C298S 36.9 ± 2.9 3.7 ± 0.8
Y74F* 0.2 ± 0.05 0.08 ± 0.03
  1. *The concentrations of the wt Trpase and of W330F, C298S mutants were 0.3-0.5 mg/ml, while the concentration of the Y74F mutant was 10-20 mg/ml.