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Molecule Parameter List for Raf-GTP-Ras*

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
Raf-GTP-Ras* participated asMoleculeSum total ofEnzymeSubstrate of an enzymeProduct of an enzymeSubstrate in ReactionProduct in Reaction
No. of occurrences1020001

Accession and Pathway Details
Accession NameAccession No.Accession TypePathway Link
  • Synaptic_
    Network
  • 16Network
    Shared_Object_Synaptic_Network PKC PLA2 
    PLCbeta Gq MAPK 
    Ras EGFR Sos 
    PLC_g CaMKII CaM 
    PP1 PP2B PKA 
    AC CaRegulation 
    This model is an annotated version of the synaptic signaling network.
    The primary reference is Bhalla US and Iyengar R. Science (1999) 283(5400):381-7 but several of the model pathways have been updated.
    Bhalla US Biophys J. 2002 Aug;83(2):740-52
    Bhalla US J Comput Neurosci. 2002 Jul-Aug;13(1):49-62

    Raf-GTP-Ras* acting as a Molecule in  
    Synaptic_Network Network
    NameAccession NamePathway NameInitial Conc.
    (uM)
    Volume
    (fL)
    Buffered
    Raf-GTP-Ras*
  • Synaptic_
    Network

    Accession No. : 16
  • MAPK
    Pathway No. : 75
    01000No
    This is the main activated form of craf. It really refers to the complex of GTP-Ras with phosphorylated Raf. See Leevers 1994 Nature 369:411-414 and Hallberg et al 1994 JBC 269(6):3913-3916. The naming is a bit awkward but kept in this model for consistency with previous models (Bhalla and Iyengar 1999 Science 283:381-387)

    Raf-GTP-Ras* acting as an Enzyme in  
    Synaptic_Network Network
     Enzyme Molecule /
    Enzyme Activity
    Accession NamePathway NameKm (uM)kcat (s^-1)RatioEnzyme TypeReagents
    1Raf-GTP-Ras* /
    Raf-GTP-Ras*.1
  • Synaptic_
    Network

    Accession No. : 16
  • MAPK
    Pathway No. : 75
    0.1590910.1054explicit E-S complexSubstrate
    MAPKK

    Product
    MAPKK-ser
        This enzyme activity refers to the complex of phosphorylated Raf and activated Ras. Starting point for 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 who report a Km of 0.8 uM and Vmax of ~500 fm/min/ug for MAPKK. These parms cannot reach the observed 4X stim of MAPK. So we increase the affinity, ie, raise k1 5X to 5.5e-6 which is equivalent to a 5x reduction in Km to about 0.16.
    2Raf-GTP-Ras* /
    Raf-GTP-Ras*.2
  • Synaptic_
    Network

    Accession No. : 16
  • MAPK
    Pathway No. : 75
    0.1590910.1054explicit E-S complexSubstrate
    MAPKK-ser

    Product
    MAPKK*
        Same kinetics as other c-raf activated forms. See Force et al PNAS 91 1270-1274 1994.

    Raf-GTP-Ras* acting as a Product in a reaction in  
    Synaptic_Network 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
    Ras-act-craf
  • Synaptic_
    Network

    Accession No. : 16
  • Shared_Object_
    Synaptic_
    Network

    Pathway No. : 70
  • 24
    (uM^-1 s^-1)
    0.5
    (s^-1)
    Kd(bf) = 0.0208(uM)-Substrate
    GTP-Ras
    craf-1*

    Product
    Raf-GTP-Ras*
    Assume binding is fast and limited only by available Ras*. So kf = kb/[craf-1] If kb is 1/sec, then kf = 1/0.2 uM = 1/(0.2 * 6e5) = 8.3e-6 Later: Raise it by 10 X to about 1e-4, giving a Kf of 60 for Kb of 0.5 and a tau of approx 2 sec. Based on: Hallberg et al JBC 269:6 3913-3916 1994, 3% of cellular Raf is complexed with Ras. This step needed to memb-anchor and activate Raf: Leevers et al Nature 369 411-414. Also see Koide et al 1993 PNAS USA 90(18):8683-8686



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