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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. | Kf | Kb | Kd | tau | Reagents | |
| 1 | CaTraspATPase | CaRegulation 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 | 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 | IP3Rbind | CaRegulation 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 | Ca | CaRegulation Pathway No. 86 | 0 (#^-2 s^-1) | 1 (s^-1) | Not applicable** | - | Substrate: Ca-sequester Ca-sequester 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. |