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Result: 1 - 9 of 9 rows are displayed

Reaction List for pathway Gq (Pathway Number 334) in Accession Ajay_Bhalla_2004_PKM_MKP3_Tuning (Accession Number 77)

Entries are grouped according to Pathway Number and they are alternately color coded using  and  color.
Further ordering can be done to the table header.  indicates that ordering is done according to ascending or descending order.
Keq is calculated only for first order reactions.
Kd is calculated only for second order reactions. [nA+nB <->nC or nA<->nC+nD, where n is number and A,B,C,D are molecules]
  Reaction
Name
Pathway Name / 
Pathway No.
KfKbKdtauReagents
1 
  • RecLigandBinding
  • Gq

    Pathway No. 334
    16.8003
    (uM^-1 s^-1)
    10
    (s^-1)
    Kd(bf) = 0.5952(uM)-  Substrate:
     mGluR
     Glu

     Products:
     Rec-Glu
      kf = kf from text = 1e7 / M / sec = 10 /uM/sec = 10 / 6e5 / # / sec = 1.67e-5 kb = kr from text = 60 / sec Note that we continue to use uM here since [phenylephrine] is also in uM. From Martin et al FEBS Lett 316:2 191-196 1993 we have Kd = 600 nM Assuming kb = 10/sec, we get kf = 10/(0.6 uM * 6e5) = 2.8e-5 1/sec/#
    2 Basal-Act-GGq

    Pathway No. 334
    0.0001
    (s^-1)
    0
    (uM^-1 s^-1)
    --  Substrate:
     G-GDP

     Products:
     G*GTP
     BetaGamma
      kf = kg1 = 0.01/sec, kb = 0. This is the basal exchange of GTP for GDP.
    3 Trimerize-GGq

    Pathway No. 334
    6
    (uM^-1 s^-1)
    0
    (s^-1)
    --  Substrate:
     G*GDP
     BetaGamma

     Products:
     G-GDP
      kf == kg3 = 1e-5 /cell/sec. As usual, there is no back-reaction kb = 0
    4 Inact-GGq

    Pathway No. 334
    0.0133
    (s^-1)
    0
    (s^-1)
    --  Substrate:
     G*GTP

     Products:
     G*GDP
      From Berstein et al JBC 267:12 8081-8088 1992, kcat for GTPase activity of Gq is only 0.8/min
    5 Rec-Glu-bind-GqGq

    Pathway No. 334
    0.006
    (uM^-1 s^-1)
    0.0001
    (s^-1)
    Kd(bf) = 0.0167(uM)-  Substrate:
     G-GDP
     Rec-Glu

     Products:
     Rec-Glu-Gq
      This is the k1-k2 equivalent for enzyme complex formation in the binding of Rec-Glu to Gq. See Fay et al Biochem 30 5066-5075 1991. kf = 5e-5 which is nearly the same as calculated by Fay et al. (4.67e-5) kb = .04 June 1996: Closer reading of Fay et al suggests that kb <= 0.0001, so kf = 1e-8 by detailed balance. This reaction appears to be neglible.
    6 Glu-bind-Rec-GqGq

    Pathway No. 334
    16.8003
    (uM^-1 s^-1)
    0.1
    (s^-1)
    Kd(bf) = 0.006(uM)-  Substrate:
     Glu
     Rec-Gq

     Products:
     Rec-Glu-Gq
      From Fay et al kb3 = kb = 1.06e-3 which is rather slow. k+1 = kf = 2.8e7 /M/sec= 4.67e-5/sec use 5e-5. However, the Kd from Martin et al may be more appropriate, as this is Glu not the system from Fay. kf = 2.8e-5, kb = 10 Let us compromise. since we have the Fay model, keep kf = k+1 = 2.8e-5. But kb (k-3) is .01 * k-1 from Fay. Scaling by .01, kb = .01 * 10 = 0.1
    7 Activate-GqGq

    Pathway No. 334
    0.01
    (s^-1)
    0
    (uM^-2 s^-1)
    --  Substrate:
     Rec-Glu-Gq

     Products:
     G*GTP
     BetaGamma
     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.
    8 Rec-bind-GqGq

    Pathway No. 334
    0.6
    (uM^-1 s^-1)
    1
    (s^-1)
    Kd(bf) = 1.6667(uM)-  Substrate:
     G-GDP
     mGluR

     Products:
     Rec-Gq
      Lets try out the same kinetics as the Rec-Glu-bind-Gq This is much too forward. We know that the steady-state amount of Rec-Gq should be 40% of the total amount of receptor. This is for a different receptor, still we can try to match the value. kf = 1e-6 and kb = 1 give 0.333:0.8 which is pretty close.
    9 
  • Antag-bind-Rec-G
    q
  • Gq

    Pathway No. 334
    60.0003
    (uM^-1 s^-1)
    0.01
    (s^-1)
    Kd(bf) = 0.0002(uM)-  Substrate:
     Rec-Gq
     mGluRAntag

     Products:
     Blocked-rec-Gq
      The rate consts give a total binding affinity of only

     
    Result: 1 - 9 of 9 rows are displayed



    Database compilation and code copyright (C) 2005, Upinder S. Bhalla and NCBS/TIFR
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