TABLE 3

Kinetic characterization and specific activities of MhIHL and its mutants

ProteinKm (mM)kcat (s−1)kcat/Km (s−1 · mM−1)Sp act (U/mg)E valuea
Wild type12 ± 2200 ± 2015.772,520 ± 200b
Val54Ser mutant18 ± 1.8140 ± 108.21,280 ± 30>200
Val54Leu mutant29 ± 3190 ± 106.7900 ± 20>200
V54Thr mutant29 ± 249 ± 31.7145 ± 9>200
Val112Ala mutant38 ± 511 ± 0.90.344 ± 3>200
His51Ala mutant40 ± 572 ± 51.8160 ± 10185
Phe110Ala-Val112Gly mutant39 ± 37.8 ± 1.20.225 ± 3>200
  • a E value is calculated by E = ln[(1 − Conv.)(1 − ee)]/ln[(1 − Conv.)(1 + ee)], where Conv. is the conversion ratio.

  • b The reaction time is long enough to calculate the E value.