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Reaction List for pathway PLA2 (Pathway Number 36) in Accession mkp1_feedback_effects (Accession Number 4)

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.
KfKbKdtauReagents
1 Degrade-AAPLA2

Pathway No. 36
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
2 PLA2-Ca-actPLA2

Pathway No. 36
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.
3 PIP2-PLA2-actPLA2

Pathway No. 36
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.
4 
  • PIP2-Ca-PLA2-act
  • PLA2

    Pathway No. 36
    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 DAG-Ca-PLA2-actPLA2

    Pathway No. 36
    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.
    6 PLA2*-Ca-actPLA2

    Pathway No. 36
    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. 36
    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.

     
    Result: 1 - 7 of 7 rows are displayed



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