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Molecule Parameter List for GAP

The statistics table lists the distribution of a molecule acting either as a substrate, product, enzyme or as a molecule within the network.
The text color of a molecule is highlighted by color.
Statistics
GAP participated asMoleculeSum total ofEnzymeSubstrate of an enzymeProduct of an enzymeSubstrate in ReactionProduct in Reaction
No. of occurrences1011001

Accession and Pathway Details
Accession NameAccession No.Accession TypePathway Link
EGFR_MAPK58Network
Shared_Object_EGFR_MAPK MAPK Ras 
EGFR Sos 
Model of MAPK activation by EGFR in the synapse. Demonstration programs using this model are available here.
Primary citation:Bhalla US. Biophys J. (2004) 87(2):745-53.

GAP acting as a Molecule in  
EGFR_MAPK Network
NameAccession NamePathway NameInitial Conc.
(uM)
Volume
(fL)
Buffered
GAPEGFR_MAPK
Accession No. : 58
Ras
Pathway No. : 231
0.0021000No
GTPase-activating proteins. See Boguski and McCormick. Turn off Ras by helping to hydrolyze bound GTP. This one is probably NF1, ie., Neurofibromin as it is inhibited by AA and lipids, and expressed in neural cells. p120-GAP is also a possible candidate, but is less regulated. Both may exist at similar levels. See Eccleston et al JBC 268(36) pp27012-19 Level=.002

GAP acting as an Enzyme in  
EGFR_MAPK Network
Enzyme Molecule /
Enzyme Activity
Accession NamePathway NameKm (uM)kcat (s^-1)RatioEnzyme TypeReagents
GAP /
GAP-inact-ras
EGFR_MAPK
Accession No. : 58
Ras
Pathway No. : 231
1.01039104explicit E-S complexSubstrate
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.

GAP acting as a Substrate for an Enzyme in  
EGFR_MAPK Network
Enzyme Molecule /
Enzyme Activity
Accession NamePathway NameKm (uM)kcat (s^-1)RatioEnzyme TypeReagents
PKC-active  /
PKC-inact-GAP
EGFR_MAPK
Accession No. : 58
  • Shared_Object_
    EGFR_MAPK

    Pathway No. : 229
  • 3.3333344explicit E-S complexSubstrate
    GAP

    Product
    GAP*
    Rate consts copied from PCK-act-raf This reaction inactivates GAP. The idea is from the Boguski and McCormick review.

    GAP acting as a Product in a reaction in  
    EGFR_MAPK Network
    Kd is calculated only for second order reactions, like nA+nB <->nC or nA<->nC+nD, where n is number and A,B,C,D are molecules, where as for first order reactions Keq is calculated. Kd for higher order reaction are not consider.
    NameAccession NamePathway NameKfKbKdtauReagents
    dephosph-GAPEGFR_MAPK
    Accession No. : 58
    Ras
    Pathway No. : 231
    0.1
    (s^-1)
    0
    (s^-1)
    --Substrate
    GAP*

    Product
    GAP
    Assume a reasonably good rate for dephosphorylating it, 1/sec



    Database compilation and code copyright (C) 2022, Upinder S. Bhalla and NCBS/TIFR
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