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Molecule Parameter List for PLA2*

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
PLA2* participated asMoleculeSum total ofEnzymeSubstrate of an enzymeProduct of an enzymeSubstrate in ReactionProduct in Reaction
No. of occurrences1000120

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

    PLA2* acting as a Molecule in  
    Synaptic_Network Network
    NameAccession NamePathway NameInitial Conc.
    (uM)
    Volume
    (fL)
    Buffered
    PLA2*
  • Synaptic_
    Network

    Accession No. : 16
  • PLA2
    Pathway No. : 72
    01000No
    Phosphorylated PLA2. The site differs from the site phosphorylated by PKC. See Nemenoff et al 1993 JBC 268(3):1960-1964

    PLA2* acting as a Product of an Enzyme in  
    Synaptic_Network Network
    Enzyme Molecule /
    Enzyme Activity
    Accession NamePathway NameKm (uM)kcat (s^-1)RatioEnzyme TypeReagents
    MAPK*  /
    MAPK*
  • Synaptic_
    Network

    Accession No. : 16
  • Shared_Object_
    Synaptic_
    Network

    Pathway No. : 70
  • 25.641204explicit E-S complexSubstrate
    PLA2-cytosolic

    Product
    PLA2*
    Km = 25uM @ 50 uM ATP and 1mg/ml MBP (huge XS of substrate) Vmax = 4124 pmol/min/ml at a conc of 125 pmol/ml of enz. Numbers are from Sanghera et al JBC 265 pp 52 , 1990. From Nemenoff et al 1993 JBC 268(3):1960-1964 - using Sanghera's 1e-4 ratio of MAPK to protein, we get k3 = 7/sec from 1000 pmol/min/mg total protein in fig 5 I take the Vmax to be higher for PLA2 given the fold activation of PLA2 by MAPK. This is actually a balance term between MAPK and the dephosphorylation step.

    PLA2* acting as a Substrate 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
    1PLA2*-Ca-act
  • Synaptic_
    Network

    Accession No. : 16
  • PLA2
    Pathway No. : 72
    6
    (uM^-1 s^-1)
    0.1
    (s^-1)
    Kd(bf) = 0.0167(uM)-Substrate
    Ca
    PLA2*

    Product
    PLA2*-Ca
      Nemenoff et al 1993 JBC 268:1960 report a 2X to 4x activation of PLA2 by MAPK, which seems dependent on Ca as well. This reaction represents this activation. Rates are scaled to give appropriate fold activation.
    2
  • dephosphorylate-
    PLA2*
  • Synaptic_
    Network

    Accession No. : 16
  • PLA2
    Pathway No. : 72
    0.17
    (s^-1)
    0
    (s^-1)
    --Substrate
    PLA2*

    Product
    PLA2-cytosolic
      Dephosphorylation reaction to balance MAPK phosphorylation of PLA2. This is probably mediated by PP2A. Rates determined to keep the balance of phosphorylated and non-phosphorylated PLA2 reasonable. The constraining factor is the fold activation of PLA2 by MAPK.



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