| |
Enzyme Molecule /
Enzyme Activity | Pathway Name /
Pathway No. | Km
(uM) | kcat
(s^-1) | Ratio
(k2/k3) | Enzyme Type | Reagents |
| 1 | MAPKK* /
MAPKKtyr | MAPK
Pathway No. 35 | 0.0462963 | 0.15 | 4 | explicit E-S complex | Substrate:
MAPK
Product :
MAPK-tyr
|
| | The actual MAPKK is 2 forms from Seger et al JBC 267:20 14373(1992) Vmax = 150nmol/min/mg From Haystead et al FEBS 306(1):17-22 we get Km=46.6nM for at least one of the phosphs. Putting these together: k3=0.15/sec, ratio of 4 to get k2=0.6. k1=0.75/46.6nM=2.7e-5 In terms of Michaelis-Menten rates, Km = 0.046, Vmax = 0.15, ratio = 4. |
| 2 | MAPKK* /
MAPKKthr | MAPK
Pathway No. 35 | 0.0462963 | 0.15 | 4 | explicit E-S complex | Substrate:
MAPK-tyr
Product :
MAPK*
|
| | Rate consts same as for MAPKKtyr. |
| 3 | RGR /
RGR.1 | MAPK
Pathway No. 35 | 0.159091 | 0.105 | 4 | explicit E-S complex | Substrate:
MAPKK
Product :
MAPKK-ser
|
| | Kinetics are the same as for the craf-1* activity, ie., k1=5.5e-6, k2=.42, k3 =0.105 These are based on Force et al PNAS USA 91 1270-1274 1994. |
| 4 | RGR /
RGR.2 | MAPK
Pathway No. 35 | 0.159091 | 0.105 | 4 | explicit E-S complex | Substrate:
MAPKK-ser
Product :
MAPKK*
|
| | Same kinetics as other c-raf activated forms. See Force et al PNAS 91 1270-1274 1994. k1 = 5.5e-6, k2 = .42, k3 = 0.105 |
| 5 | MKP-1** /
MKP1*-tyr-deph | MAPK
Pathway No. 35 | 0.0666667 | 1 | 4 | Classical Michaelis-Menten
V = Etot.S.Kcat/Km+S | Substrate:
MAPK-tyr
Product :
MAPK
|
| | 3 Feb 2000. Same rates as MKP-1. |
| 6 | MKP-1** /
MKP1*-thr-deph | MAPK
Pathway No. 35 | 0.0666667 | 1 | 4 | Classical Michaelis-Menten
V = Etot.S.Kcat/Km+S | Substrate:
MAPK*
Product :
MAPK-tyr
|
| | 3 Feb 2000. Same rates as MKP1 |
| 7 | nuc_MAPK* /
act_
transcription | MAPK
Pathway No. 35 | 4.00002 | 0.0008 | 4 | explicit E-S complex | Substrate:
Nucleotides
Product :
MKP1-RNA
|
| | This is a 'black box' representation of a lot of steps. Constraint provided by determining rate of formation of MKP-1. |
| 8 | Raf*-GTP-Ras /
Raf*-GTP-Ras.1 | MAPK
Pathway No. 35 | 0.159091 | 0.105 | 4 | explicit E-S complex | Substrate:
MAPKK
Product :
MAPKK-ser
|
| | Kinetics are the same as for the craf-1* activity, ie., k1=1.1e-6, k2=.42, k3 =0.105 These are based on Force et al PNAS USA 91 1270-1274 1994. They report Km for MAPKK of 0.8 uM. and a Vmax of ~500 fm/min/ug. These parms cannot reach the observed 4X stimulation of MAPK. So we increase the affinity, ie, raise k1 5x to 5.5e-6 which is equivalent to 5-fold reduction in Km to about 0.16. This is, of course, dependent on the amount of MAPKK present. |
| 9 | Raf*-GTP-Ras /
Raf*-GTP-Ras.2 | MAPK
Pathway No. 35 | 0.159091 | 0.105 | 4 | explicit E-S complex | Substrate:
MAPKK-ser
Product :
MAPKK*
|
| | Same kinetics as other c-raf activated forms. See Force et al PNAS 91 1270-1274 1994. |
and 
color.
arrow indicates that ordering is done according to ascending or descending order.