Table 2.
Enzyme kinetics and sequence analysis of xylA mutantsa
| Gene | Vmax (μmol mg protein−1 min−1) | Km (mM) | Mutations |
|---|---|---|---|
| xylA | 0.053 ± 0.007 | 86.97 ± 6.56 | |
| xylA*1 | 0.064 ± 0.001 | 89.98 ± 3.93 | E129D, V433I |
| xylA*2 | 0.083 ± 0.002 | 50.18 ± 7.08 | E129D, V433I, E15D, E114G |
| xylA*3 | 0.094 ± 0.006 | 168.39 ± 11.98 | E129D, V433I, E15D, E114G, T142S, A177T |
a
The wild-type (xylA) xylose isomerase gene and first-round (xylA*1), second-round (xylA*2), and third-round (xylA*3) mutants were expressed in S. cerevisiae, and in vitro xylose isomerase activity was measured and reported. Sequence analysis revealed the mutations identified in each round. The standard deviations of biological triplicates are indicated.