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Molecule Parameter List for IP3R*

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
IP3R* participated asMoleculeSum total ofEnzymeSubstrate of an enzymeProduct of an enzymeSubstrate in ReactionProduct in Reaction
No. of occurrences1000001

Accession and Pathway Details
Accession NameAccession No.Accession TypePathway Link
  • NonOsc_Ca_
    IP3metabolism
  • 31Network
    MIPP CaMKII CaM 
    PKC IP3-3K CaRegulation 
    Gq PLCbeta 134_dephos 
    145_dephos IP4-system IHP-system 
    1345_dephos 
    This network models detailed metabolism of Ins(145)P3, integrated with GPCR mediated PLCbeta activation and Ca release by the InsP3 receptor in the neuron. It is similar to the NonOsc_Ca_IP3metab model (accession 23) except that some enzymes have been modified to have reversible kinetics rather than Michaelis-Menten kinetics. These modified enzymes belong to the groups: IP4-system, IP3-3K, 145_dephos and 134_dephos. Mishra J, Bhalla US. Biophys J. 2002 Sep;83(3):1298-316.

    IP3R* acting as a Molecule in  
    NonOsc_Ca_IP3metabolism Network
    NameAccession NamePathway NameInitial Conc.
    (uM)
    Volume
    (fL)
    Buffered
    IP3R*
  • NonOsc_Ca_
    IP3metabolism

    Accession No. : 31
  • CaRegulation
    Pathway No. : 149
    01000No
    This is the ligand-bound form of the IP3R.

    IP3R* acting as a Product in a reaction in  
    NonOsc_Ca_IP3metabolism 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
    IP3Rbind
  • NonOsc_Ca_
    IP3metabolism

    Accession No. : 31
  • CaRegulation
    Pathway No. : 149
    0.05
    (uM^-3 s^-1)
    1
    (s^-1)
    Kd(af) = 2.7144(uM)-Substrate
    IP3
    IP3
    IP3
    IP3R

    Product
    IP3R*
    Based on Lauffenburger and Linderman 1993 Receptors pg 200. The binding of IP3 on this reaction had a Hill coeff of 3. The eqns of Mahama and Linderman (cited in the book as 1993 a) are equivalent to the binding all occurring in a single step, so that is how I do it in this version. Their Ki1 is 0.07 uM. Lots of other data sources: Ramos-Franco et al, Biophys J 75, 1998: 834-39 have Ca sensitivity curves. At 250 nM free Ca, the EC50 for type1 is 58 nM and type 2 is 194 nM. Type 3 would be about 2 uM according to Newton et al, JBC 268(46), 1994: 28613-19. For the purposes of this model we use a Kd of 2.7 uM which is high but maybe OK at low calcium. The details of Ca interaction with the IP3R are not included in this model.



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