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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 | Synaptic_
Network | 16 | Network |
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 |
MAPK acting as a Molecule in Synaptic_Network Network
| Name | Accession Name | Pathway Name | Initial Conc.
(uM) | Volume
(fL) | Buffered | | MAPK | Synaptic_
Network
Accession No. : 16 | MAPK
Pathway No. : 75 | 0.36 | 1000 | No | | Mol wt is 42 KDa. conc is from Sanghera et al JBC 265 pp 52 (1990) They estimate MAPK is 1e-4x total protein, and protein is 15% of cell wt, so MAPK is 1.5e-5g/ml = 0.36uM. Lets use this. Note though that Huang and Ferrell 1996 PNAS 93(19):10078 report 1.2 uM in oocytes. Also note that brain concs may be high. Ortiz et al 1995 J. Neurosci 15(2):1285-1297 report 0.3 ng/ug protein in Cingulate Gyrus and 1.2 ng/ug protein in nucleus accumbens. In hippocampus 270 ng/mg protein for ERK1 and 820 ng/mg protein for ERK 2. If 15% of cell weight is protein, that means that about 300 * 0.15 ng/ul is ERK 1. ie, 45e-9g/1e-6 litre = 45 mg/litre or about 1 uM. For non-neuronal tissues a lower value may be better. |
MAPK acting as a Substrate for an Enzyme in Synaptic_Network Network
Enzyme Molecule /
Enzyme Activity | Accession Name | Pathway Name | Km (uM) | kcat (s^-1) | Ratio | Enzyme Type | Reagents | MAPKK* /
MAPKKtyr | Synaptic_
Network
Accession No. : 16 | MAPK
Pathway No. : 75 | 0.0462963 | 0.15 | 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, ratio of 4 to get k2=0.6. k1=0.75/46.6nM=2.7e-5 In terms of Michaelis-Menten rates, Km = 0.046, Vmax = 0.15, ratio = 4. |
MAPK acting as a Product of an Enzyme in Synaptic_Network Network
Enzyme Molecule /
Enzyme Activity | Accession Name | Pathway Name | Km (uM) | kcat (s^-1) | Ratio | Enzyme Type | Reagents | MKP-1 /
MKP1-tyr-deph | Synaptic_
Network
Accession No. : 16 | Shared_Object_
Synaptic_
Network
Pathway No. : 70 | 0.0666667 | 1 | 4 | explicit E-S complex | Substrate
MAPK-tyr
Product
MAPK
| | The original kinetics from Bhalla and Iyengar Science 1999 have now been modified to obey the k2 = 4 * k3 rule, while keeping kcat and Km fixed. The main constraining data point is the time course of MAPK dephosphorylation, which this model satisfies. See Charles et al 1993 PNAS 90:5292-5296 and Charles et al Oncogene 7:187-190 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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