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Molecule Parameter List for PPhosphatase2A | 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 |
| PPhosphatase2A 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 | 4 | 0 | 0 | 0 | 0 |
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. |
PPhosphatase2A acting as a Molecule in mkp1_feedback_effects Network
| Name | Accession Name | Pathway Name | Initial Conc.
(uM) | Volume
(fL) | Buffered | | PPhosphatase2A | mkp1_feedback_
effects
Accession No. : 4 | Shared_Object_
mkp1_feedback_
effects
Pathway No. : 32 | 0.224 | 1000 | No | CoInit values span a range depending on the source Pato MD, Sutherland C, Winder SJ, Walsh MP. (1993) Biochem J. 293 ( Pt 1):35-41; and Cohen P, Alemany S, Hemmings BA, Resink TJ, Stralfors P, Tung HY. (1988) Methods Enzymol. 159:390-408 estimate 80 nM from muscle. Zolnierowicz S, Csortos C, Bondor J, Verin A, Mumby MC, DePaoli-Roach AA. (1994) Biochemistry 33(39):11858-11867 report levels of 0.4 uM again from muscle, but expression is also strong in brain. Our estimate of 0.224 is between these two.
There are many substrates for PP2A in this model, so I put the enzyme rate calculations here: Takai A and Mieskes G (1991) Biochem J. 275 ( Pt 1):233-9 have mol wt 36 KDa. They report Vmax of 119 umol/min/mg i.e. 125/sec for k3 for pNPP substrate, Km of 16 mM. This is obviously unreasonable for protein substrates. For chicken gizzard myosin light chan, we have Vmax = 13 umol/min/mg or about k3 = 14/sec. Pato MD, Sutherland C, Winder SJ, Walsh MP. (1993) Biochem J. 293 ( Pt 1):35-41 report caldesmon: Km = 2.2 uM, Vmax = 0.24 umol/min/mg. They do not think caldesmon is a good substrate. Calponin: Km = 14.3, Vmax = 5. Our values approximate these. |
PPhosphatase2A acting as an Enzyme in mkp1_feedback_effects Network
| | Enzyme Molecule /
Enzyme Activity | Accession Name | Pathway Name | Km (uM) | kcat (s^-1) | Ratio | Enzyme Type | Reagents | | 1 | PPhosphatase2A /
craf-deph
| mkp1_feedback_
effects
Accession No. : 4 | Shared_Object_
mkp1_feedback_
effects
Pathway No. : 32 | 15.6566 | 6 | 4.16667 | explicit E-S complex | Substrate
craf-1*
Product
craf-1
| | | See parent PPhosphatase2A for parms | | 2 | PPhosphatase2A /
MAPKK-deph
| mkp1_feedback_
effects
Accession No. : 4 | Shared_Object_
mkp1_feedback_
effects
Pathway No. : 32 | 15.6566 | 6 | 4.16667 | explicit E-S complex | Substrate
MAPKK*
Product
MAPKK-ser
| | | See: Kyriakis JM, App H, Zhang XF, Banerjee P, Brautigan DL, Rapp UR, Avruch J. (1992) Nature 358(6385):417-21. Ahn NG, Seger R, Krebs EG. (1992) Curr Opin Cell Biol. 4(6):992-999 for this pathway. Refer parent PPhosphatase2A for parameters. | | 3 | PPhosphatase2A /
MAPKK-deph-ser
| mkp1_feedback_
effects
Accession No. : 4 | Shared_Object_
mkp1_feedback_
effects
Pathway No. : 32 | 15.6566 | 6 | 4.16667 | explicit E-S complex | Substrate
MAPKK-ser
Product
MAPKK
| | | See parent PPhostphatase2A description for rate details | | 4 | PPhosphatase2A /
craf**-deph
| mkp1_feedback_
effects
Accession No. : 4 | Shared_Object_
mkp1_feedback_
effects
Pathway No. : 32 | 15.6566 | 6 | 4.16667 | explicit E-S complex | Substrate
craf-1**
Product
craf-1*
| | | Ueki K, Matsuda S, Tobe K, Gotoh Y, Tamemoto H, Yachi M, Akanuma Y, Yazaki Y, Nishida E, Kadowaki T. (1994) J Biol Chem. 269(22):15756-61show hyperphosphorylation of craf, so this is there to dephosphorylate it. Identity of phosphatase is assumed to be PP2A. |
| Database compilation and code copyright (C) 2022, Upinder S. Bhalla and NCBS/TIFR
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