TABLE 1.

Measured properties of native and variant enzymes

The k_obs^rel values of evolution activities were calculated as described for Fig. 3. Zn²⁺-binding constants (K_i) were determined for native and variant enzymes at 0.50 mm ZnCl₂. -Fold stimulation values are the ratio of enzyme activity with and without the addition of 250 mm sodium azide (n = 3–8).

	kobsrel (evolution)	Ki	Stimulation
		mm	-fold
Native	1.00	171 ± 25	0.89
C299S	0.00a	477 ± 36	0.28b
E279D	0.00a	236 ± 68	0.73b
E279L	0.01	283 ± 99	0.30b
S319A	0.01	107 ± 8	1.30b
E282D	0.14	383 ± 10	2.37
E282L	0.04	3550 ± 98	3.57b

^a Although small, a statistically significant amount of activity was noted for this variant enzyme (k_obs^rel = 4.0 × 10⁻⁴).

^b p < 0.1.