TABLE 2.

Activity and kinetic parameters of the variant proteins

Protein	Specific activitya	Kdb compound 1	Kdc compound 4
	pmol/min/mg	μm	μm
yCT	2.31 ± 0.06	7.8 ± 2.0	50.0 ± 15.0
hCT	4.07 ± 0.59	1.0 ± 0.2	28.0 ± 5.0
yCT-H9	1.32 ± 0.10	4.8 ± 2.0	37.0 ± 6.0

^a Values were determined from carboxyltransferase assays.

^b Estimated K_d values were determined from fluorescence antisotropy binding assay using the intrinsic fluorescent property of this compound (Fig. 4A).

^c K_d values were estimated using compound 4 as a competitor for the binding of compound 1 (Fig. 4B).