and 18, whereas an almost 10-fold higher specific activity was obtained with haloalcohol 20. Therefore, also kinetic parameters of HheG-682 in the dehalogenation of 2-chlorocyclohexanol (20) were determined and compared to respective literature data for HheG (Table ). This revealed a 5.2-times higher kcat of HheG-682, while the K50 was also increased two-fold, resulting in an overall higher catalytic efficiency of HheG-682 in the dehalogenation of 20 compared to HheG. Interestingly, both enzymes displayed strong cooperativity for binding of haloaclohol 20 with Hill coefficients of 2.9 and 3.2 for HheG and HheG-682, respectively. (20) determined with a halide release assay. Reactions were carried out in a total volume of 1 mL with 10 mM haloalcohol in 25 mM Tris•SO4 buffer, pH 7.0, at 30 °C using either 200 µg mL -1 HheG or 150 µg mL -1 HheG-682. Samples were taken after 30, 60, 90, 120, 150, 180 s as duplicates. Chemical background of negative control reactions without enzyme addition was subtracted. The resulting specific activities exhibit standard deviations between 0.0 and 0.2 U mg -1 .