| |
Reaction
Name | Pathway Name /
Pathway No. | Kf | Kb | Kd | tau | Reagents |
| 1 | PLA2-Ca-act | PLA2
Pathway No. 72 | 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. | | 2 | PIP2-PLA2-act | PLA2
Pathway No. 72 | 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 | PIP2-Ca-PLA2-act | PLA2
Pathway No. 72 | 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 | | 4 | DAG-Ca-PLA2-act | PLA2
Pathway No. 72 | 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. | | 5 | Degrade-AA | PLA2
Pathway No. 72 | 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 | | 6 | PLA2*-Ca-act | PLA2
Pathway No. 72 | 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. | | 7 | dephosphorylate-
PLA2* | PLA2
Pathway No. 72 | 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. |
and 
color.
indicates that ordering is done according to ascending or descending order.