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Reaction List for pathway PLA2 (Pathway Number 183) in Accession MAPK-bistability-fig1c (Accession Number 35) |
Entries are grouped according to Pathway Number and they are alternately color coded using  and  color.
Further ordering can be done to the table header.   indicates that ordering is done according to ascending or descending order.Keq is calculated only for first order reactions. Kd is calculated only for second order reactions. [nA+nB <->nC or nA<->nC+nD, where n is number and A,B,C,D are molecules] |
| Reaction Name | Pathway Name / Pathway No. | Kf | Kb | Kd | tau | Reagents | |
| 1 | DAG-Ca-PLA2-act | PLA2 Pathway No. 183 | 0.003 (uM^-1 s^-1) | 4 (s^-1) | Kd(bf) = 1333.3333(uM) | - | Substrate: DAG PLA2-Ca* Products: DAG-Ca-PLA2* | Synergistic activation of PLA2 by Ca and DAG. Based on Leslie and Channon 1990 BBA 1045:261 The Kd is rather large and may reflect the complications in measuring DAG. For this model it is not critical since DAG is held fixed. |
| 2 | PIP2-PLA2-act | PLA2 Pathway No. 183 | 0.0012 (uM^-1 s^-1) | 0.5 (s^-1) | Kd(bf) = 416.6667(uM) | - | Substrate: temp-PIP2 PLA2-cytosolic Products: PIP2-PLA2* | Activation of PLA2 by PIP2. From Leslie and Channon 1990 BBA 1045:261 the stimulation of PLA2 activity by high PIP2 is 7x. In this model we don't really expect any PIP2 stimulus. |
| 3 | PLA2-Ca-act | PLA2 Pathway No. 183 | 1 (uM^-1 s^-1) | 0.1 (s^-1) | Kd(bf) = 0.1(uM) | - | Substrate: PLA2-cytosolic Ca Products: PLA2-Ca* | Direct activation of PLA2 by Ca. From Leslie and Channon BBA 1045 (1990) 261-270 fig6 pp267. |
| 4 | | PLA2 Pathway No. 183 | 0.012 (uM^-1 s^-1) | 0.1 (s^-1) | Kd(bf) = 8.3333(uM) | - | Substrate: temp-PIP2 PLA2-Ca* Products: PIP2-Ca-PLA2* | Synergistic activation of PLA2 by Ca and PIP2. Again from Leslie and Channon 1990 BBA 1045:261 |
| 5 | PLA2*-Ca-act | PLA2 Pathway No. 183 | 6 (uM^-1 s^-1) | 0.1 (s^-1) | Kd(bf) = 0.0167(uM) | - | Substrate: PLA2* Ca Products: PLA2*-Ca | Nemenoff et al 1993 JBC 268:1960 report a 2X to 4x activation of PLA2 by MAPK, which seems dependent on Ca as well. This reaction represents this activation. Rates are scaled to give appropriate fold activation. |
| 6 | Degrade-AA | PLA2 Pathway No. 183 | 0.4 (s^-1) | 0 (s^-1) | - | - | Substrate: AA Products: APC | Degradation pathway for AA. APC is a convenient buffered pool to dump it back into, though the actual metabolism is probably far more complex. For the purposes of the full model we use a rate of degradation of 0.4/sec to give a dynamic range of AA comparable to what is seen experimentally. Wijkander and Sundler 1991 Eur J Biochem 202:873 Leslie and Channon 1990 BBA 1045:261 |
| 7 | PLA2* | PLA2 Pathway No. 183 | 0.17 (s^-1) | 0 (s^-1) | - | - | Substrate: PLA2* Products: PLA2-cytosolic | Dephosphorylation reaction to balance MAPK phosphorylation of PLA2. This is probably mediated by PP2A. Rates determined to keep the balance of phosphorylated and non-phosphorylated PLA2 reasonable. The constraining factor is the fold activation of PLA2 by MAPK. |