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Molecule Parameter List for PP1-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
PP1-I1* participated asMoleculeSum total ofEnzymeSubstrate of an enzymeProduct of an enzymeSubstrate in ReactionProduct in Reaction
No. of occurrences1002001

Accession and Pathway Details
Accession NameAccession No.Accession TypePathway Link
  • Synaptic_
    Network
  • 16Network
    Shared_Object_Synaptic_Network PKC PLA2 
    PLCbeta Gq MAPK 
    Ras EGFR Sos 
    PLC_g CaMKII CaM 
    PP1 PP2B PKA 
    AC CaRegulation 
    This model is an annotated version of the synaptic signaling network.
    The primary reference is Bhalla US and Iyengar R. Science (1999) 283(5400):381-7 but several of the model pathways have been updated.
    Bhalla US Biophys J. 2002 Aug;83(2):740-52
    Bhalla US J Comput Neurosci. 2002 Jul-Aug;13(1):49-62

    PP1-I1* acting as a Molecule in  
    Synaptic_Network Network
    NameAccession NamePathway NameInitial Conc.
    (uM)
    Volume
    (fL)
    Buffered
    PP1-I1*
  • Synaptic_
    Network

    Accession No. : 16
  • PP1
    Pathway No. : 82
    01000No
    This form has the inibitory fragment phosphorylated. The binding of PP1 is tight when the inhibitory fragment is phosphorylated Cohen 1989 Ann Rev Biochem 58:453-508

    PP1-I1* acting as a Substrate for an Enzyme in  
    Synaptic_Network Network
     Enzyme Molecule /
    Enzyme Activity
    Accession NamePathway NameKm (uM)kcat (s^-1)RatioEnzyme TypeReagents
    1CaM(Ca)n-CaNAB  /
    dephosph-PP1-I*
  • Synaptic_
    Network

    Accession No. : 16
  • Shared_Object_
    Synaptic_
    Network

    Pathway No. : 70
  • 4.970760.344explicit E-S complexSubstrate
    PP1-I1*

    Product
    PP1-I1
        Liu and Storm JBC 1989 264(22):12800-12804 say Km ~ 5 uM, Vmax = 256 nmol/min/mg ~ 0.34/sec
    2PP2A  /
  • PP2A-dephosph-PP
    1-I*
  • Synaptic_
    Network

    Accession No. : 16
  • Shared_Object_
    Synaptic_
    Network

    Pathway No. : 70
  • 7.8282864.16667explicit E-S complexSubstrate
    PP1-I1*

    Product
    PP1-I1
        PP2A does most of the dephosph of I1 at basal Ca levels. See the review by Cohen in Ann Rev Biochem 1989 58:453-508 I use a Km twice that for the preferred substrates of PP2A. Here I assume that the dephosph of the PP1-bound form of I1* will proceed at the same rate as the unbound I1*.

    PP1-I1* acting as a Product in a reaction in  
    Synaptic_Network 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
    Inact-PP1
  • Synaptic_
    Network

    Accession No. : 16
  • PP1
    Pathway No. : 82
    499.98
    (uM^-1 s^-1)
    0.1
    (s^-1)
    Kd(bf) = 0.0002(uM)-Substrate
    I1*
    PP1-active

    Product
    PP1-I1*
    K inhib = 1nM from Cohen Ann Rev Bioch 1989, 4 nM from Foukes et al Assume 2 nM. kf /kb = 8.333e-4 The Kd used here is 0.2 nM. This is small, but unlikely to matter much as the affinity is so strong that the reaction will be all the way forward in either case. Tau < 1 min for inhibition. Stralfors 1985 Eur J Biochem 149:295-303 fig 8 pg 201.



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