TABLE 1

Kinetic Parameters for FAC and Its Analogs with l-Chirality

Probe	K_M (μM)	Relative k_cat	Relative k_cat/K_M
FAC	0.76 ± 0.15	1.0	1.0
l-FMAC	1.02 ± 0.15	1.0	0.96
l-FCAC	0.61 ± 0.09	0.96	1.20
l-FBAC	6.54 ± 0.99	2.70	0.31

k_cat and specificity constant (k_cat/K_M) were determined using purified recombinant human dCK, and values are given relative to FAC.