Enzyme

pH optima

Apparent pKa

Wild-type

~5.0/9.0

~4.5; 5.5; 6.5; ~9.0

E40H

6.0 - 8.0

~5.5

E44H

6.0 - 8.0

~5.5

E40H/E44H

7.5 - 10.0

~7.0

D186H

6.5 - 8.0

~6.5

D186N

5.5 - 12

~5.5