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Molecule Parameter List for MAPK | 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) |
MAPK acting as a Molecule in Ajay_Bhalla_2007_Bistable Network
| Name | Accession Name | Pathway Name | Initial Conc.
(uM) | Volume
(fL) | Buffered | | MAPK | Ajay_Bhalla_
2007_Bistable
Accession No. : 79 | MAPK
Pathway No. : 366 | 3.6 | 125.7 | No | | conc is from Sanghera et al JBC 265 pp 52 (1990) A second calculation gives 3.1 uM, from same paper. They est MAPK is 1e-4x total protein, and protein is 15% of cell wt, so MAPK is 1.5e-5g/ml = 0.36uM. which is closer to our first estimate. Lets use this. Updated 16 May 2003. Ortiz et al 1995 J Neurosci 15(2):1285-1297 provide estimates of ERK2 levels in hippocampus: 1009 ng/mg. This comes to about 3.6uM, which may still be an underestimate of synaptic levels. |
MAPK acting as a Substrate for 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 | MAPKK* /
MAPKKtyr | Ajay_Bhalla_
2007_Bistable
Accession No. : 79 | MAPK
Pathway No. : 366 | 0.0462968 | 0.3 | 4 | explicit E-S complex | Substrate
MAPK
Product
MAPK-tyr
| | The actual MAPKK is 2 forms from Seger et al JBC 267:20 14373(1992) Vmax = 150nmol/min/mg From Haystead et al FEBS 306(1):17-22 we get Km=46.6nM for at least one of the phosphs. Putting these together: k3=0.15/sec, scale to get k2=0.6. k1=0.75/46.6nM=2.7e-5 |
MAPK 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 | MKP-1 /
MKP1-tyr-deph | Ajay_Bhalla_
2007_Bistable
Accession No. : 79 | Shared_Object_
Ajay_Bhalla_
2007_Bistable
Pathway No. : 363 | 0.133331 | 4 | 4 | explicit E-S complex | Substrate
MAPK-tyr
Product
MAPK
| | The original kinetics have been modified to obey the k2 = 4 * k3 rule, while keeping kcat and Km fixed. As noted in the NOTES, the only constraining data point is the time course of MAPK dephosphorylation, which this model satisfies. It would be nice to have more accurate estimates of rate consts and MKP-1 levels from the literature. Effective Km : 67 nM kcat = 1.43 umol/min/mg |
| Database compilation and code copyright (C) 2022, Upinder S. Bhalla and NCBS/TIFR
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