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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 |
Accession and Pathway Details | |
| Accession Name | Accession No. | Accession Type | Pathway Link | Ajay_Bhalla_
2007_Bistable | 79 | Network |
Shared_Object_Ajay_Bhalla_2007_Bistable, PKC, PLA2,
MAPK, Ras, CaM | This is a model of ERKII signaling which is bistable due to feedback. The feedback occurs through ERKII phosphorylation of phospholipase A2 (PLA2), leading to increased production of arachidonic acid (AA), which activates protein kinase C (PKC) which activates c-Raf which is upstream of ERKII.
The model is a highly simplified variant of more detailed bistable models of MAPK signaling (Bhalla US, Iyengar R. Science. 1999 Jan 15;283(5400):381-7, Ajay SM, Bhalla US. Eur J Neurosci. 2004 Nov;20(10):2671-80) |
PLA2* acting as a Molecule in Ajay_Bhalla_2007_Bistable Network
PLA2* acting as a Product of an Enzyme in Ajay_Bhalla_2007_Bistable Network
Enzyme Molecule /
Enzyme Activity | Accession Name | Pathway Name | Km (uM) | kcat (s^-1) | Ratio | Enzyme Type | Reagents | MAPK* /
MAPK* | Ajay_Bhalla_
2007_Bistable
Accession No. : 79 | Shared_Object_
Ajay_Bhalla_
2007_Bistable
Pathway No. : 363 | 25.6402 | 10 | 4 | explicit E-S complex | Substrate
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, so: k3 = .5/sec (rate limiting) k1 = (k2 + k3)/Km = (.5 + 0)/(25*6e5) = 2e-8 (#/cell)^-1 #s from Sanghera et al JBC 265 pp 52 , 1990. From Nemenoff et al 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 fig 5 |
PLA2* acting as a Substrate in a reaction in Ajay_Bhalla_2007_Bistable 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 | Ajay_Bhalla_
2007_Bistable
Accession No. : 79 | PLA2
Pathway No. : 365 | 6
(uM^-1 s^-1) | 0.1
(s^-1) | Kd(bf) = 0.0167(uM) | - | Substrate
Ca
PLA2*
Product
PLA2*-Ca
| | | To start off, same kinetics as the PLA2-Ca-act direct pathway. Oops ! Missed out the Ca input to this pathway first time round. Let's raise the forward rate about 3x to 5e-6. This will let us reduce the rather high rates we have used for the kenz on PLA2*-Ca. In fact, it may be that the rates are not that different, just that this pathway for getting the PLA2 to the memb is more efficien.... | | 2 | dephosphorylate-
PLA2* | Ajay_Bhalla_
2007_Bistable
Accession No. : 79 | PLA2
Pathway No. : 365 | 0.17
(s^-1) | 0
(s^-1) | - | - | Substrate
PLA2*
Product
PLA2-cytosolic
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| Database compilation and code copyright (C) 2022, Upinder S. Bhalla and NCBS/TIFR
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