Protein
Substrate
Km (μM)
Vmaxa
Kcat (s-1) Kcat/ Km (s-1 μM -1)
SaMbcS isobutyrate (iC4) 8.9 ± 2.1 1.6 ± 0.3 0.43 ± 0.09 0.049
2-methylbutyrate (aC5) 5.5 ± 1.0 0.8 ± 0.2 0.23 ± 0.05 0.042
isovalerate (iC5) > 500 NDb NDb NDb
SaMbcSK510A 2-methylbutyrate (aC5) NDb NDb NDb NDb
RpIbuAWT isobutyrate (iC4) 72.3 ± 26.9 5.4 ± 1.6 3.01 ± 0.87 0.042
All values are mean ± standard deviation aμM of AMP produced min-1 bNot determined; enzyme is catalytically inactive. All values are mean ± standard deviation aμM of AMP produced min-1 bNot determined; enzyme is catalytically inactive.