| | Name | Kf | Kb | Kd | tau | Substrate | Product |
| 1 |
DAG-Ca-PLA2-act | kf
(uM^-1 s^-1) | 4
(s^-1) | Kd(bf) = 1333.3333(uM) | - | DAG
PLA2-Ca*
| 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 |
Degrade-AA | kf
(s^-1) | 0
(s^-1) | - | - | AA
| 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 |
| 3 |
dephosphorylate-
PLA2* | kf
(s^-1) | 0
(s^-1) | - | - | PLA2*
| 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. |
| 4 |
PIP2-Ca-PLA2-act | kf
(uM^-1 s^-1) | 0.1
(s^-1) | Kd(bf) = 8.3333(uM) | - | temp-PIP2
PLA2-Ca*
| PIP2-Ca-PLA2*
|
| | Synergistic activation of PLA2 by Ca and PIP2. Again from Leslie and Channon 1990 BBA 1045:261 |
| 5 |
PIP2-PLA2-act | kf
(uM^-1 s^-1) | 0.5
(s^-1) | Kd(bf) = 416.6667(uM) | - | temp-PIP2
PLA2-cytosolic
| 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. |
| 6 |
PLA2*-Ca-act | kf
(uM^-1 s^-1) | 0.1
(s^-1) | Kd(bf) = 0.0167(uM) | - | PLA2*
Ca
| 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. |
| 7 |
PLA2-Ca-act | kf
(uM^-1 s^-1) | 0.1
(s^-1) | Kd(bf) = 0.1(uM) | - | PLA2-cytosolic
Ca
| PLA2-Ca*
|
| | Direct activation of PLA2 by Ca. From Leslie and Channon BBA 1045 (1990) 261-270 fig6 pp267. |
