Table II. Steady-state kinetic parameters of wild-type and mutant HheC with the substrate para-nitro-2-bromo-1-phenylethanol.

Enzyme	Km (mM)	kcat (s–1)	kcat/Km (s–1M–1)
Wild typea	0.009 ± 0.003	22 ± 1	2.4 × 106
Ser132Alab	–d	–d	–d
Tyr145Pheb	0.13	0.072	5.5 × 102
Arg149Lysb	0.056	0.33	5.9 × 103
Arg149Asnb	>0.40	>0.15	3.8 × 102
Asp80Asnc	0.02 ± 0.002	0.1 ± 0.002	5.0 × 103
Asp80Alac	–d	–d	–d

^aData taken from Tang et al. (2003).

^bData taken from van Hylckama Vlieg et al. (2001).

^cThis study.

^dNo activity detectable.