Cation
|
a
Optimal concentration
|
b
Maximal extension rate
|
b
Average extension rate
|
---|
mM
|
nts/sec
|
nts/sec
|
---|
Mg2+
| 2 (1.6) | 7.4 ± 1.9 | 1.8 ± 0.5 |
Mn2+
| 0.4 (0.15) | 1.2 ± 0.3 | 0.48 ± 0.09 |
Co2+
| 0.25 (0.07) | 1.1 ± 0.1 | 0.23 ± 0.05 |
Zn2+
| 0.4 (0.15) | 0.19 ± 0.10 | 0.03 ± 0.02 |
-
aThe concentration of free cation is shown in parenthesis. Free cation concentration for Mg2+ was calculated as described in Materials and Methods using the dissociation constant for Mg2+ and ATP. Free concentrations for alternative cations (Mn2+, Co2+, and Zn2+) were approximately using the dissociation constant for Mg2+ and ATP.
-
bValues are averages from 3 experiments ± standard deviation. Rates were calculated as described in Materials and Methods.