Table 2.
Simulations of Rapid Quench Flow Kinetic Transients for SRPK1 Mutants
| Protein | [E]a (μM) |
[ATP]a (μM) |
[E•SRn]b (μM) |
k1[ATP]c (s−1) |
k2 (s−1)b | k3 (S−1)b | koff (s−1)b |
|---|---|---|---|---|---|---|---|
| SRPK1 | 0.25 | 600 | 0.20 | 54 | 30 | 1.1 | 1.1 |
| SRPK1(ΔS) | 0.60 | 600 | 0.60 | 3 | 7 | 0.085 | 0.10 |
| SRPK1(ΔN) | 0.60 | 600 | 0.51 | 6 | 4 | 0.10 | 0.10 |
| SRPK1(ΔSINT) | 1.0 | 600 | 0.77 | 12 | 69 | 0.94 | 1.0 |
| SRPK1(ΔSα1) | 0.30 | 600 | 0.30 | 12 | 19 | 0.18 | 0.19 |
| SRPK1(I228G) | 1.0 | 50 | 0.65 | 2.5 | 50 | 1.1 | |
| SRPK1(ΔNNT) | 0.50 | 50 | 0.45 | 3 | 50 | 0.86 | |
| SRPK1(ΔNSα1) | 0.50 | 600 | 0.46 | 5 | 12 | 0.10 | 0.10 |
a
Total amounts of enzyme and ATP in kinetic experiments.
b
Values from kinetic simulations using DynaFit and the mechanism in Fig. 2B that best fit the kinetic transients in the absence or presence of preequilibrated ADP.
c
Values for k1[ATP] are fixed from the product of total [ATP] and kcat/KATP.