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Molecule Parameter List for G*GTP

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
G*GTP participated asMoleculeSum total ofEnzymeSubstrate of an enzymeProduct of an enzymeSubstrate in ReactionProduct in Reaction
No. of occurrences1000032

Accession and Pathway Details
Accession NameAccession No.Accession TypePathway Link
  • Ajay_Bhalla_
    2004_Feedback_
    Tuning
  • 78Network
    Shared_Object_Ajay_Bhalla_2004_Feedback_Tuning PKC PLA2 
    PLCbeta Gq MAPK 
    Ras EGFR Sos 
    PLC_g CaMKII CaM 
    PP1 PP2B PKA 
    AC 
    This model is taken from Ajay SM, Bhalla US. Eur J Neurosci. 2004 Nov;20(10):2671-80. This is the feedback model from Figure 8a.

    G*GTP acting as a Molecule in  
    Ajay_Bhalla_2004_Feedback_Tuning Network
    NameAccession NamePathway NameInitial Conc.
    (uM)
    Volume
    (fL)
    Buffered
    G*GTP
  • Ajay_Bhalla_
    2004_Feedback_
    Tuning

    Accession No. : 78
  • Shared_Object_
    Ajay_Bhalla_
    2004_Feedback_
    Tuning

    Pathway No. : 347
  • 01.5No
    Activated G protein. Berstein et al indicate that about 20-40% of the total Gq alpha should bind GTP at steady stim. This sim gives more like 65%.

    G*GTP acting as a Substrate in a reaction in  
    Ajay_Bhalla_2004_Feedback_Tuning 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
    1Act-PLC-by-Gq
  • Ajay_Bhalla_
    2004_Feedback_
    Tuning

    Accession No. : 78
  • PLCbeta
    Pathway No. : 350
    25.2
    (uM^-1 s^-1)
    1
    (s^-1)
    Kd(bf) = 0.0397(uM)-Substrate
    G*GTP
    PLC-Ca

    Product
    PLC-Ca-Gq
      Affinity for Gq is > 20 nM (Smrcka et al Science251 804-807 1991) so [Gq].kf = kb so 40nM * 6e5 = kb/kf = 24e3 so kf = 4.2e-5, kb =1
    2PLC-bind-Gq
  • Ajay_Bhalla_
    2004_Feedback_
    Tuning

    Accession No. : 78
  • PLCbeta
    Pathway No. : 350
    2.52
    (uM^-1 s^-1)
    1
    (s^-1)
    Kd(bf) = 0.3968(uM)-Substrate
    G*GTP
    PLC

    Product
    PLC-Gq
      this binding does not produce active PLC. This step was needed to implement the described (Smrcka et al) increase in affinity for Ca by PLC once Gq was bound. The kinetics are the same as the binding step for Ca-PLC to Gq. June 1996: Changed the kf to 4.2e-5 to 4.2e-6 to preserve balance around the reactions.
    3Inact-G
  • Ajay_Bhalla_
    2004_Feedback_
    Tuning

    Accession No. : 78
  • Gq
    Pathway No. : 351
    0.0133
    (s^-1)
    0
    (s^-1)
    --Substrate
    G*GTP

    Product
    G*GDP
      From Berstein et al JBC 267:12 8081-8088 1992, kcat for GTPase activity of Gq is only 0.8/min

    G*GTP acting as a Product in a reaction in  
    Ajay_Bhalla_2004_Feedback_Tuning 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
  • Ajay_Bhalla_
    2004_Feedback_
    Tuning

    Accession No. : 78
  • Gq
    Pathway No. : 351
    0.0001
    (s^-1)
    0
    (uM^-1 s^-1)
    --Substrate
    G-GDP

    Product
    BetaGamma
    G*GTP
      kf = kg1 = 0.01/sec, kb = 0. This is the basal exchange of GTP for GDP.
    2Activate-Gq
  • Ajay_Bhalla_
    2004_Feedback_
    Tuning

    Accession No. : 78
  • Gq
    Pathway No. : 351
    0.01
    (s^-1)
    0
    (uM^-2 s^-1)
    --Substrate
    Rec-Glu-Gq

    Product
    BetaGamma
    G*GTP
    Rec-Glu
      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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