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Accession Type:
Network
EGFR_MAPK
Shared_Object_
EGFR_MAPK
MAPK
Ras
 Molecule
 Enzyme
 Reaction
EGFR
Sos

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Enzyme List for pathway Ras (Pathway Number 231)

 Molecule Name/
Site Name
Km (uM) kcat (1/s)Ratio
(k2/k3)
Enzyme TypeSubstrate Product
1 Enzyme Activity:
CaM-GEF-act-ras

Enzyme Molecule:
CaM-GEF
0.5050510.024explicit E-S complexGDP-Ras
GTP-Ras
  Kinetics same as GEF-bg_act-ras
2 Enzyme Activity:
GAP-inact-ras

Enzyme Molecule:
GAP
1.01039104explicit E-S complexGTP-Ras
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.
3 Enzyme Activity:
GEF*-act-ras

Enzyme Molecule:
GEF*
0.5050510.024explicit E-S complexGDP-Ras
GTP-Ras
  Kinetics same as GEF-bg-act-ras
4 Enzyme Activity:
GEF-bg_act-ras

Enzyme Molecule:
GEF-Gprot-bg
0.5050510.024explicit E-S complexGDP-Ras
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


Pathway Details   Molecule List  Enzyme List   Reaction List  


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