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Molecule Parameter List for I1

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
I1 participated asMoleculeSum total ofEnzymeSubstrate of an enzymeProduct of an enzymeSubstrate in ReactionProduct in Reaction
No. of occurrences2002602

Accession and Pathway Details
Accession NameAccession No.Accession TypePathway Link
CaMKII_model363Network
Shared_Object_CaMKII_model3 CaMKII CaM 
PP1 PP2B PP1_PSD 
AC PKA 
This is the complete model of CaMKII bistability, model 3. It exhibits bistability in CaMKII activation due to autophosphorylation at the PSD and local saturation of PP1. This version of model 3 includes PKA regulatory input. This has little effect on the deterministic calculations, but the PKA pathway introduces a lot of noise which causes a difference in stochastic runs.

I1 acting as a Molecule in  
CaMKII_model3 Network
NameAccession NamePathway NameInitial Conc.
(uM)
Volume
(fL)
Buffered
I1CaMKII_model3
Accession No. : 63
PP1
Pathway No. : 266
1.80.09No
I1 is a 'mixed' inhibitor, but at high enz concs it looks like a non-compet inhibitor (Foulkes et al Eur J Biochem 132 309-313 9183). We treat it as non-compet, so it just turns the enz off without interacting with the binding site. Cohen et al ann rev bioch refer to results where conc is 1.5 to 1.8 uM. In order to get complete inhib of PP1, which is at 1.8 uM, we need >= 1.8 uM.
I1CaMKII_model3
Accession No. : 63
PP1_PSD
Pathway No. : 268
40.01No
I1 is a 'mixed' inhibitor, but at high enz concs it looks like a non-compet inhibitor (Foulkes et al Eur J Biochem 132 309-313 9183). We treat it as non-compet, so it just turns the enz off without interacting with the binding site. Cohen et al ann rev bioch refer to results where conc is 1.5 to 1.8 uM. In order to get complete inhib of PP1, which is at 1.8 uM, we need >= 1.8 uM.

I1 acting as a Substrate for an Enzyme in  
CaMKII_model3 Network
 Enzyme Molecule /
Enzyme Activity
Accession NamePathway NameKm (uM)kcat (s^-1)RatioEnzyme TypeReagents
1PKA-active  /
PKA-phosph-I1
CaMKII_model3
Accession No. : 63
  • Shared_Object_
    CaMKII_model3

    Pathway No. : 263
  • 7.5000894explicit E-S complexSubstrate
    I1

    Product
    I1*
        #s from Bramson et al CRC crit rev Biochem 15:2 93-124. They have a huge list of peptide substrates and I have chosen high-ish rates. These consts give too much PKA activity, so lower Vmax 1/3. Now, k1 = 3e-5, k2 = 36, k3 = 9 (still pretty fast). Also lower Km 1/3 so k1 = 1e-5 Cohen et al FEBS Lett 76:182-86 1977 say rate =30% PKA act on phosphokinase beta.
    2PKA-active  /
  • PKA-phosph-I1_
    PSD
  • CaMKII_model3
    Accession No. : 63
  • Shared_Object_
    CaMKII_model3

    Pathway No. : 263
  • 7.5000894explicit E-S complexSubstrate
    I1

    Product
    I1*

    I1 acting as a Product of an Enzyme in  
    CaMKII_model3 Network
     Enzyme Molecule /
    Enzyme Activity
    Accession NamePathway NameKm (uM)kcat (s^-1)RatioEnzyme TypeReagents
    1PP2A  /
  • PP2A-dephosph-I1
  • CaMKII_model3
    Accession No. : 63
  • Shared_Object_
    CaMKII_model3

    Pathway No. : 263
  • 15.999924.1667explicit E-S complexSubstrate
    I1*

    Product
    I1
        PP2A does most of the dephosph of I1 at basal Ca levels. See the review by Cohen in Ann Rev Biochem 1989. For now, lets halve Km. k1 was 3.3e-6, now 6.6e-6
    2PP2A  /

  • PP2A-dephosph-I1
    _
    PSD
  • CaMKII_model3
    Accession No. : 63
  • Shared_Object_
    CaMKII_model3

    Pathway No. : 263
  • 15.999924.1667explicit E-S complexSubstrate
    I1*

    Product
    I1
        PP2A does most of the dephosph of I1 at basal Ca levels. See the review by Cohen in Ann Rev Biochem 1989. For now, lets halve Km. k1 was 3.3e-6, now 6.6e-6
    3CaNAB-Ca4  /
  • dephosph_
    inhib1_noCaM
  • CaMKII_model3
    Accession No. : 63
  • Shared_Object_
    CaMKII_model3

    Pathway No. : 263
  • 4.970790.0344explicit E-S complexSubstrate
    I1*

    Product
    I1
        The rates here are so slow I do not know if we should even bother with this enz reacn. These numbers are from Liu and Storm. Other refs suggest that the Km stays the same but the Vmax goes to 10% of the CaM stim levels. Prev: k1=2.2e-9, k2 = 0.0052, k3 = 0.0013 New : k1=5.7e-8, k2=.136, k3=.034
    4CaNAB-Ca4  /
  • dephosph_
    inhib1_noCaM_
    PSD
  • CaMKII_model3
    Accession No. : 63
  • Shared_Object_
    CaMKII_model3

    Pathway No. : 263
  • 4.970710.0344explicit E-S complexSubstrate
    I1*

    Product
    I1
        The rates here are so slow I do not know if we should even bother with this enz reacn. These numbers are from Liu and Storm. Other refs suggest that the Km stays the same but the Vmax goes to 10% of the CaM stim levels. Prev: k1=2.2e-9, k2 = 0.0052, k3 = 0.0013 New : k1=5.7e-8, k2=.136, k3=.034
    5CaM_Ca_n-CaNAB  /
    dephosph_inhib1
    CaMKII_model3
    Accession No. : 63
  • Shared_Object_
    CaMKII_model3

    Pathway No. : 263
  • 4.970790.344explicit E-S complexSubstrate
    I1*

    Product
    I1
    6CaM_Ca_n-CaNAB  /
  • dephosph_
    inhib1_PSD
  • CaMKII_model3
    Accession No. : 63
  • Shared_Object_
    CaMKII_model3

    Pathway No. : 263
  • 4.970710.344explicit E-S complexSubstrate
    I1*

    Product
    I1

    I1 acting as a Product in a reaction in  
    CaMKII_model3 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
    1dissoc-PP1-I1CaMKII_model3
    Accession No. : 63
    PP1
    Pathway No. : 266
    1
    (s^-1)
    0
    (uM^-1 s^-1)
    --Substrate
    PP1-I1

    Product
    I1
    PP1-active
      Let us assume that the equil in this case is very far over to the right. This is probably safe.
    2dissoc-PP1-I1CaMKII_model3
    Accession No. : 63
    PP1_PSD
    Pathway No. : 268
    1
    (s^-1)
    0
    (uM^-1 s^-1)
    --Substrate
    PP1-I1

    Product
    I1
    PP1-active_PSD
      Let us assume that the equil in this case is very far over to the right. This is probably safe.



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