Table II.

Kinetic parameters for IPMS1 and IPMS2

EnzymeSubstrateKm (μm) ± seVmax (μmol min−1 g−1) ± sekcat (s−1)kcat/Km (m−1 s−1)
IPMS12-Oxoisovaleratea304 ± 682.3 × 103 ± 0.2 × 1032.47.8 × 103
Acetyl-CoAb45 ± 102.1 × 103 ± 0.1 × 1032.24.7 × 104
IPMS22-Oxoisovaleratea279 ± 512.2 × 103 ± 0.1 × 1032.38.3 × 103
Acetyl-CoAb16 ± 41.8 × 103 ± 0.1 × 1031.91.2 × 105
  • a Measured in the presence of 500 μm acetyl-CoA.

  • b Measured in the presence of 1 mm 2-oxoisovalerate.