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Molecule Parameter List for BetaGamma

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
BetaGamma participated asMoleculeSum total ofEnzymeSubstrate of an enzymeProduct of an enzymeSubstrate in ReactionProduct in Reaction
No. of occurrences1000022

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

    BetaGamma acting as a Molecule in  
    Synaptic_Network Network
    NameAccession NamePathway NameInitial Conc.
    (uM)
    Volume
    (fL)
    Buffered
    BetaGamma
  • Synaptic_
    Network

    Accession No. : 16
  • Shared_Object_
    Synaptic_
    Network

    Pathway No. : 70
  • 01000No
    The betagamma subunits of Gq. This is an approximation to the possible combinations of betagamma subunits. Here they are all treated as a single pool.

    BetaGamma acting as a Substrate 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
    1Trimerize-G
  • Synaptic_
    Network

    Accession No. : 16
  • Gq
    Pathway No. : 74
    6
    (uM^-1 s^-1)
    0
    (s^-1)
    --Substrate
    BetaGamma
    G*GDP

    Product
    G-GDP
      kf == kg3 = 1e-5 /cell/sec. As usual, there is no back-reaction kb = 0
    2bg-act-GEF
  • Synaptic_
    Network

    Accession No. : 16
  • Ras
    Pathway No. : 76
    6
    (uM^-1 s^-1)
    1
    (s^-1)
    Kd(bf) = 0.1667(uM)-Substrate
    BetaGamma
    inact-GEF

    Product
    GEF-Gprot-bg
      SoS/GEF is present at 50 nM ie 3e4/cell. BetaGamma maxes out at 9e4. Assume we have 1/3 of the GEF active when the BetaGamma is 1.5e4. so 1e4 * kb = 2e4 * 1.5e4 * kf, so kf/kb = 3e-5. The rate of this equil should be reasonably fast, say 1/sec

    BetaGamma 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
    1Basal-Act-G
  • Synaptic_
    Network

    Accession No. : 16
  • Gq
    Pathway No. : 74
    0.0001
    (s^-1)
    0
    (uM^-1 s^-1)
    --Substrate
    G-GDP

    Product
    BetaGamma
    G*GTP
      This is the basal exchange of GTP for GDP. So slow as to be nearly negligible.
    2Activate-Gq
  • Synaptic_
    Network

    Accession No. : 16
  • Gq
    Pathway No. : 74
    0.01
    (s^-1)
    0
    (uM^-2 s^-1)
    --Substrate
    Rec-Glu-Gq

    Product
    BetaGamma
    G*GTP
    Rec-Glu
      This reaction is the critical one for activation of Gq. It probably encapsulates multiple steps. In this approximation the receptor-ligand- Gprotein complex splits up into GTP.Galpha, rec.ligand complex, and Gbetagamma. There is a hidden step of exchange of GDP for GTP. The reaction does not take these into account since it is assumed that both GTP and GDP levels are tightly regulated by metabolic control. This is the kcat==k3 stage of the Rec-Glu ezymatic activation of Gq. From Berstein et al actiation is at .35 - 0.7/min From Fay et al Biochem 30 5066-5075 1991 kf = .01/sec From Nakamura et al J physiol Lond 474:1 35-41 1994 see time courses. Also (Berstein) 15-40% of gprot is in GTP-bound form on stim.



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