TABLE 2.
Km,P, Km,K, Vmax,P, Vmax,K, and the residual activities in the presence of 10 mM l-valine, l-isoleucine, l-leucine, or all three BCAAs (10 mM each) of the WT AHAS or the modified AHAS ΔC-T ilvN
| Enzyme | Values for indicated substrate
|
Residual activity in the presence of 10 mM inhibitor(s) (%)a
|
||||||
|---|---|---|---|---|---|---|---|---|
| Pyruvate + pyruvate
|
α-Ketobutyrate + pyruvate
|
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| Km,P (mM) | Vmax,P (mU/mg) | Km,K (mM) | Vmax,K (mU/mg) | l-Valine | l-Isoleucine | l-Leucine | All three BCAAs | |
| Wild-type AHAS | 7.8 | 77.6 | 5.6 | 113.9 | 50 | 54 | 65 | 46 |
| AHAS ΔC-T ilvN | 4.7 | 22.3 | 6.9 | 56.8 | 104 | 104 | 104 | 107 |
a
Activities were measured using 50 mM pyruvate as the substrate. A value of 100% corresponds to 73.5 mU/mg for the WT AHAS and 22.1 mU/mg for AHAS ΔC-T ilvN.