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Molecule Parameter List for GEF-Gprot-bg

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
GEF-Gprot-bg participated asMoleculeSum total ofEnzymeSubstrate of an enzymeProduct of an enzymeSubstrate in ReactionProduct in Reaction
No. of occurrences1010001

Accession and Pathway Details
Accession NameAccession No.Accession TypePathway Link
EGFR_MAPK58Network
Shared_Object_EGFR_MAPK MAPK Ras 
EGFR Sos 
Model of MAPK activation by EGFR in the synapse. Demonstration programs using this model are available here.
Primary citation:Bhalla US. Biophys J. (2004) 87(2):745-53.

GEF-Gprot-bg acting as a Molecule in  
EGFR_MAPK Network
NameAccession NamePathway NameInitial Conc.
(uM)
Volume
(fL)
Buffered
GEF-Gprot-bgEGFR_MAPK
Accession No. : 58
Ras
Pathway No. : 231
01000No
Guanine nucleotide exchange factor. This activates raf by exchanging bound GDP with GTP. I have left the GDP/GTP out of this reaction, it would be trivial to put them in. See Boguski & McCormick. Possible candidate molecules: RasGRF, smgGDS, Vav (in dispute). rasGRF: Kcat= 1.2/min Km = 680 nM smgGDS: Kcat: 0.37 /min, Km = 220 nM. vav: Turnover up over baseline by 10X,

GEF-Gprot-bg acting as an Enzyme in  
EGFR_MAPK Network
Enzyme Molecule /
Enzyme Activity
Accession NamePathway NameKm (uM)kcat (s^-1)RatioEnzyme TypeReagents
GEF-Gprot-bg /
GEF-bg_act-ras
EGFR_MAPK
Accession No. : 58
Ras
Pathway No. : 231
0.5050510.024explicit E-S complexSubstrate
GDP-Ras

Product
GTP-Ras
Kinetics based on the activation of Gq by the receptor complex in the Gq model (in turn based on the Mahama and Linderman model) k1 = 2e-5, k2 = 1e-10, k3 = 10 (I do not know why they even bother with k2). Lets put k1 at 2e-6 to get a reasonable equilibrium More specific values from, eg.g: Orita et al JBC 268(34) 25542-25546 from rasGRF and smgGDS: k1=3.3e-7; k2 = 0.08, k3 = 0.02

GEF-Gprot-bg acting as a Product in a reaction in  
EGFR_MAPK 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
bg-act-GEFEGFR_MAPK
Accession No. : 58
Ras
Pathway No. : 231
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



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