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Molecule Parameter List for PLA2-cytosolic | 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 | Accession and Pathway Details | |
Accession Name | Accession No. | Accession Type | Pathway Link | mkp1_feedback_ effects | 4 | Network | Shared_Object_mkp1_feedback_effects, Sos, PKC, MAPK, PLA2, Ras, PDGFR | This is a network involving the MAPK-PKC feedback loop with input from the PDGFR in the synapse. The distinctive feature of this model is that it includes MKP-1 induction by MAPK, and the consequent inhibitory regulation of MAPK and the feedback loop. Lots of interesting dynamics arise from this. This link provides supplementary material for the paper Bhalla US et al. Science (2002) 297(5583):1018-23. In the form of several example simulations and demos for the figures in the paper. |
PLA2-cytosolic acting as a Molecule in mkp1_feedback_effects Network
Name | Accession Name | Pathway Name | Initial Conc. (uM) | Volume (fL) | Buffered | PLA2-cytosolic | mkp1_feedback_ effects Accession No. : 4 | PLA2 Pathway No. : 36 | 0.4 | 1000 | No | cPLA2 IV form has mol wt of 85 Kd. Glaser et al 1993 TIPS 14:92-98. Calculated cytosolic concentration is ~300 nM from Wijkander and Sundler 1991 Eur J Biochem 202:873 Leslie and Channon 1990 BBA 1045:261 use about 400 nM. Decent match. Use 400 nM. |
PLA2-cytosolic acting as a Substrate for an Enzyme in mkp1_feedback_effects Network
Enzyme Molecule / Enzyme Activity | Accession Name | Pathway Name | Km (uM) | kcat (s^-1) | Ratio | Enzyme Type | Reagents | MAPK* / MAPK* | mkp1_feedback_ effects Accession No. : 4 | Shared_Object_ mkp1_feedback_ effects Pathway No. : 32 | 25.641 | 20 | 4 | explicit E-S complex | Substrate PLA2-cytosolic
Product PLA2*
| Km for MBP = 25 uM at 50 uM ATP, Km for ATP = 58 uM at 1mg/ml MBP (huge excess of substrate), Vmax = 4124 pmol/min/ml at a concentartion of 125 pmol/ml of enzyme. Numbers are from pp. 54 Sanghera JS, Paddon HB, Bader SA, Pelech SL. (1990) J Biol Chem. 265(1):52-7. From Nemenoff RA, Winitz S, Qian NX, Van Putten V, Johnson GL, Heasley LE. (1993) J Biol Chem. 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-cytosolic acting as a Substrate in a reaction in mkp1_feedback_effects 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. |
| Name | Accession Name | Pathway Name | Kf | Kb | Kd | tau | Reagents | 1 | PLA2-Ca-act | mkp1_feedback_ effects Accession No. : 4 | PLA2 Pathway No. : 36 | 1 (uM^-1 s^-1) | 0.1 (s^-1) | Kd(bf) = 0.1(uM) | - | Substrate Ca PLA2-cytosolic
Product PLA2-Ca*
| | Direct activation of PLA2 by Ca. From Leslie and Channon BBA 1045 (1990) 261-270 fig6 pp267. | 2 | PIP2-PLA2-act | mkp1_feedback_ effects Accession No. : 4 | PLA2 Pathway No. : 36 | 0.0012 (uM^-1 s^-1) | 0.5 (s^-1) | Kd(bf) = 416.6667(uM) | - | Substrate PLA2-cytosolic temp-PIP2
Product PIP2-PLA2*
| | Activation of PLA2 by PIP2. From Leslie and Channon 1990 BBA 1045:261 the stimulation of PLA2 activity by high PIP2 is 7x. In this model we don't really expect any PIP2 stimulus. |
PLA2-cytosolic acting as a Product in a reaction in mkp1_feedback_effects 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. |
Name | Accession Name | Pathway Name | Kf | Kb | Kd | tau | Reagents | dephosphorylate- PLA2* | mkp1_feedback_ effects Accession No. : 4 | PLA2 Pathway No. : 36 | 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 This Copyright is applied to ensure that the contents of this database remain freely available. Please see FAQ for details. |
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