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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 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| MAPK participated as | Molecule | Sum total of | Enzyme | Substrate of an enzyme | Product of an enzyme | Substrate in Reaction | Product in Reaction |
| No. of occurrences | 1 | 0 | 0 | 1 | 1 | 0 | 0 |
Accession and Pathway Details |
| Accession Name | Accession No. | Accession Type | Pathway Link |
-fig1c | 35 | Network | Shared_Object_MAPK-bistability-fig1c, Sos, PKC, MAPK, PLA2, Ras, PDGFR |
| Model for figure 1c in Bhalla US et al. Science (2002) 297(5583):1018-23. The demo for this figure is available here. This synaptic signaling model is without the MKP-1 feedback, so it is bistable and remains so over long periods. | |||
MAPK acting as a Molecule in MAPK-bistability-fig1c Network
| Name | Accession Name | Pathway Name | Initial Conc. (uM) | Volume (fL) | Buffered | |
| MAPK | -fig1c Accession No. : 35 | MAPK Pathway No. : 182 | 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 MAPK-bistability-fig1c Network
| Enzyme Molecule / Enzyme Activity | Accession Name | Pathway Name | Km (uM) | kcat (s^-1) | Ratio | Enzyme Type | Reagents |
| MAPKK* / MAPKKtyr | -fig1c Accession No. : 35 | MAPK Pathway No. : 182 | 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 MAPK-bistability-fig1c Network
| Enzyme Molecule / Enzyme Activity | Accession Name | Pathway Name | Km (uM) | kcat (s^-1) | Ratio | Enzyme Type | Reagents |
| MKP-2 / MKP2-tyr-deph | -fig1c Accession No. : 35 | MAPK-bistability -fig1c Pathway No. : 179 | 0.0666667 | 1 | 4 | explicit E-S complex | Substrate MAPK-tyr Product MAPK |
| 22 Apr 2001: Based on MKP1 parms. The original kinetics have been modified to obey the k2 = 4 * k3 rule, while keeping kcat and Km fixed. The only constraining data point is the time course of MAPK dephosphorylation, which this model satisfies. The rates are treated as the same as for MKP-1, based on Chu et al 1995 JBC 271(11):6497-6501 | |||||||