NCBS Home page
Accession List
Pathway List
Search
Authorized Users
Help
News archives

Enter a Search String

Special character and space not allowed in the query term. Search string should be at least 2 characters long.
Search in: Search for Match By

Molecule Parameter List for 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
GTP-Ras participated asMoleculeSum total ofEnzymeSubstrate of an enzymeProduct of an enzymeSubstrate in ReactionProduct in Reaction
No. of occurrences1001120

Accession and Pathway Details
Accession NameAccession No.Accession TypePathway Link
  • MAPK_MKP1_
    oscillation
  • 9Network
    Shared_Object_MAPK_MKP1_oscillation PKC MAPK 
    PLA2 Ras 
    This model relates to figure 5 in Bhalla US, Iyengar R. Chaos (2001) 11(1):221-226. It includes the model used for figures 2-4 and also has MKP-1 induction by MAPK activity in the synapse. PP2A is set to 0.16 uM and MKP synthesis is varied from 5x to 40 x basal to get a range of interesting behaviours.

    GTP-Ras acting as a Molecule in  
    MAPK_MKP1_oscillation Network
    NameAccession NamePathway NameInitial Conc.
    (uM)
    Volume
    (fL)
    Buffered
    GTP-Ras
  • MAPK_MKP1_
    oscillation

    Accession No. : 9
  • Ras
    Pathway No. : 63
    01000No
    Only a very small fraction (7% unstim, 15% stim) of ras is GTP-bound. Gibbs et al JBC 265(33) 20437

    GTP-Ras acting as a Substrate for an Enzyme in  
    MAPK_MKP1_oscillation Network
    Enzyme Molecule /
    Enzyme Activity
    Accession NamePathway NameKm (uM)kcat (s^-1)RatioEnzyme TypeReagents
    GAP  /
    GAP-inact-ras
  • MAPK_MKP1_
    oscillation

    Accession No. : 9
  • Ras
    Pathway No. : 63
    1.010410100explicit 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)

    GTP-Ras acting as a Product of an Enzyme in  
    MAPK_MKP1_oscillation Network
    Enzyme Molecule /
    Enzyme Activity
    Accession NamePathway NameKm (uM)kcat (s^-1)RatioEnzyme TypeReagents
    GEF*  /
    GEF*-act-ras
  • MAPK_MKP1_
    oscillation

    Accession No. : 9
  • Ras
    Pathway No. : 63
    0.5050510.024explicit E-S complexSubstrate
    GDP-Ras

    Product
    GTP-Ras
    Kinetics same as GEF-bg-act-ras

    GTP-Ras acting as a Substrate in a reaction in  
    MAPK_MKP1_oscillation 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
    1Ras-act-craf
  • MAPK_MKP1_
    oscillation

    Accession No. : 9
  • Shared_Object_
    MAPK_MKP1_
    oscillation

    Pathway No. : 59
  • 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 4e-5 From Hallberg et al JBC 269:6 3913-3916 1994, 3% of cellular Raf is complexed with Ras. So raise kb 4x to 4e-5 This step needed to memb-anchor and activate Raf: Leevers et al Nature 369 411-414.
    2
  • Ras-intrinsic-GT
    Pase
  • MAPK_MKP1_
    oscillation

    Accession No. : 9
  • Ras
    Pathway No. : 63
    0.0001
    (s^-1)
    0
    (s^-1)
    --Substrate
    GTP-Ras

    Product
    GDP-Ras
      This is extremely slow (1e-4), but it is significant as so little GAP actually gets complexed with it that the total GTP turnover rises only by 2-3 X (see Gibbs et al, JBC 265(33) 20437-20422) and Eccleston et al JBC 268(36) 27012-27019 kf = 1e-4



    Database compilation and code copyright (C) 2022, Upinder S. Bhalla and NCBS/TIFR
    This Copyright is applied to ensure that the contents of this database remain freely available. Please see FAQ for details.