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Result: 1 - 4 of 4 rows are displayed

Reaction List for pathway CaRegulation (Pathway Number 86) in Accession Synaptic_Network (Accession Number 16)

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 CaTraspATPaseCaRegulation

Pathway No. 86
25
(s^-1)
0
(#^-2 s^-1)
Not applicable**-  Substrate:
 CaTransp-2Ca

 Products:
 CaTransp
 Ca-sequester
 Ca-sequester
  kCa3 = 2 * Ca transporter rate since each step has 2 Ca++. = 0.5 uM/sec from Lauffenburger and Linderman 1993 Receptors pg 200. The amount of the activated transporter is about 0.01 uM = 6e3 #. from runs. So 0.01uM * kf * 2 = 0.5 uM/sec (no back reaction) so kf = 25, kb = 0 Alternatively, 6e3 * kf = 0.25 * 6e5, giving the same kf
2 
  • Ca-bind-to-Trans
    p
  • CaRegulation

    Pathway No. 86
    3600
    (uM^-2 s^-1)
    144
    (s^-1)
    Kd(bf) = 0.04(uM)-  Substrate:
     Ca_intracell
     Ca_intracell
     CaTransp

     Products:
     CaTransp-2Ca
      Rates from Lauffenberger and Linderman 1993 Receptors pg 200. Kd = KCa2 = 0.2 uM.
    3 IP3RbindCaRegulation

    Pathway No. 86
    0.05
    (uM^-3 s^-1)
    1
    (s^-1)
    Kd(af) = 2.7144(uM)-  Substrate:
     IP3R
     IP3
     IP3
     IP3

     Products:
     IP3R*
      Based on Lauffenburger and Linderman 1993 Receptors page 200. The binding of IP3 in this reaction has a Hill coeff of 3. The eqns of Mahama and Linderman (cited in the book as 1993 a) are equivalent to the binding all occurring in a single step, so that is how I am doing it in this version. Their Ki1 is 0.07 uM. Lots of other data sources: Ramos-Franco et al 1998 Biophys J 75:834-839 have Ca sensitivity curves. At 250 nM free Ca, the EC50 for type 1 is 58 nM and type 2 is 194 nM. Type 3 would be about 2 uM according to Newton et al 1994 JBC 268(46):28613-28619 For the purposes of this model we use a Kd of 2.7 uM which is high but may be OK at low calcium. The details of Ca interaction with the IP3R are not included in this model.
    4 
  • inactivate_cap_
    Ca
  • CaRegulation

    Pathway No. 86
    0
    (#^-2 s^-1)
    1
    (s^-1)
    Not applicable**-  Substrate:
     Ca-sequester
     Ca-sequester
  •  capacitive_Ca_
    entry*


     Products:
     inact_cap_entry
  •   The Kd is set to about 3 uM, so that at resting Ca the capacitive Ca entry is almost blocked. A 2nd order response makes the response steep.
    ** This is a trasport reation between compartments of different volumes. Therefore Kd is not applicable. Please Note Kf, Kb units are in number of molecules instead of concentration

     
    Result: 1 - 4 of 4 rows are displayed



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