| |
Enzyme Molecule /
Enzyme Activity | Pathway Name /
Pathway No. | Km
(uM) | kcat
(s^-1) | Ratio
(k2/k3) | Enzyme Type | Reagents |
| 1 | GEF-Gprot-bg /
GEF-bg_act-ras | Ras
Pathway No. 333 | 0.505051 | 0.02 | 4 | explicit E-S complex | Substrate:
GDP-Ras
Product :
GTP-Ras
|
| | Kinetics based on the activation of Gq by the receptor complex in the Gq model (in turn based on the Mahama and Linderman model) k1 = 2e-5, k2 = 1e-10, k3 = 10 (I do not know why they even bother with k2). Lets put k1 at 2e-6 to get a reasonable equilibrium More specific values from, eg.g: Orita et al JBC 268(34) 25542-25546 from rasGRF and smgGDS: k1=3.3e-7; k2 = 0.08, k3 = 0.02 |
| 2 | GEF* /
GEF*-act-ras | Ras
Pathway No. 333 | 0.505051 | 0.02 | 4 | explicit E-S complex | Substrate:
GDP-Ras
Product :
GTP-Ras
|
| | Kinetics same as GEF-bg-act-ras |
| 3 | GAP /
GAP-inact-ras | Ras
Pathway No. 333 | 1.01039 | 10 | 4 | explicit E-S complex | Substrate:
GTP-Ras
Product :
GDP-Ras
|
| | From Eccleston et al JBC 268(36)pp27012-19 get Kd < 2uM, kcat - 10/sec From Martin et al Cell 63 843-849 1990 get Kd ~ 250 nM, kcat = 20/min I will go with the Eccleston figures as there are good error bars (10%). In general the values are reasonably close. k1 = 1.666e-3/sec, k2 = 1000/sec, k3 = 10/sec (note k3 is rate-limiting) 5 Nov 2002: Changed ratio term to 4 from 100. Now we have k1=8.25e-5; k2=40, k3=10. k3 is still rate-limiting. |
| 4 | CaM-GEF /
CaM-GEF-act-ras | Ras
Pathway No. 333 | 0.505051 | 0.02 | 4 | explicit E-S complex | Substrate:
GDP-Ras
Product :
GTP-Ras
|
| | Kinetics same as GEF-bg_act-ras |
and 
color.
arrow indicates that ordering is done according to ascending or descending order.