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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. 211 | 0.0462963 | 0.15 | 4 | explicit E-S complex | Substrate: MAPK Product : MAPK-tyr
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| 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, scale to get k2=0.6. k1=0.75/46.6nM=2.7e-5 |
2 | MAPKK* / MAPKKthr | MAPK
Pathway No. 211 | 0.0462963 | 0.15 | 4 | explicit E-S complex | Substrate: MAPK-tyr Product : MAPK*
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| Rate consts same as for MAPKKtyr. |
3 | Raf-GTP-Ras* / Raf-GTP-Ras*.1 | MAPK
Pathway No. 211 | 0.159091 | 0.105 | 4 | explicit E-S complex | Substrate: MAPKK Product : MAPKK-ser
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| 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. These parms cannot reach the observed 4X stim of MAPK. So lets increase the affinity, ie, raise k1 10X to 1.1e-5 Lets take it back down to where it was. Back up to 5X: 5.5e-6 |
4 | Raf-GTP-Ras* / Raf-GTP-Ras*.2 | MAPK
Pathway No. 211 | 0.159091 | 0.105 | 4 | explicit E-S complex | Substrate: MAPKK-ser Product : MAPKK*
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| Same kinetics as other c-raf activated forms. See Force et al PNAS 91 1270-1274 1994. k1 = 1.1e-6, k2 = .42, k3 = 1.05 raise k1 to 5.5e-6 |