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Reaction List for pathway CaRegulation (Pathway Number 149) in Accession NonOsc_Ca_IP3metabolism (Accession Number 31)

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	Ca-bind-to-Trans p	CaRegulation Pathway No. 149	3600 (uM^-2 s^-1)	144 (s^-1)	Kd(af) = 0.2(uM)	-	Substrate: Ca Ca CaTransp Products: CaTransp-2Ca
	Rates from Lauffenburger abd Linderman 1993 Receptors pg 200. Kd = KCa2 = 0.2 uM
2	Ca5-bind-Cal	CaRegulation Pathway No. 149	0.0005 (uM^-5 s^-1)	1 (s^-1)	-	-	Substrate: Calseq Ca-sequester Ca-sequester Ca-sequester Ca-sequester Ca-sequester Products: Ca5-Cal
	There are actually 5 Ca-sequester substrates for this reaction, along with one Calseq. Due to system limitations only four are entered.
3	IP3Rbind	CaRegulation Pathway No. 149	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 pg 200. The binding of IP3 on this reaction had 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 do it in this version. Their Ki1 is 0.07 uM. Lots of other data sources: Ramos-Franco et al, Biophys J 75, 1998: 834-39 have Ca sensitivity curves. At 250 nM free Ca, the EC50 for type1 is 58 nM and type 2 is 194 nM. Type 3 would be about 2 uM according to Newton et al, JBC 268(46), 1994: 28613-19. For the purposes of this model we use a Kd of 2.7 uM which is high but maybe 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. 149	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 at about 3 uM so that at resting Ca the capacitative Ca entry is almost blocked. A 2nd order response makes the response steep.
5	Ca10-bind-Cal	CaRegulation Pathway No. 149	0.0005 (uM^-5 s^-1)	1 (s^-1)	-	-	Substrate: Ca5-Cal Ca-sequester Ca-sequester Ca-sequester Ca-sequester Ca-sequester Products: Ca10-Cal
	There are actually 5 Ca-sequester substrates for this reaction, along with Ca5-Cal. Due to system limitations only four are entered.
6	Ca15-bind-Cal	CaRegulation Pathway No. 149	0.0005 (uM^-5 s^-1)	1 (s^-1)	-	-	Substrate: Ca10-Cal Ca-sequester Ca-sequester Ca-sequester Ca-sequester Ca-sequester Products: Ca15-Cal
	There are actually 5 Ca-sequester substrates for this reaction, along with Ca10-Cal. Due to system limitations only four are entered.
7	Ca20-bind-Cal	CaRegulation Pathway No. 149	0.0005 (uM^-5 s^-1)	1 (s^-1)	-	-	Substrate: Ca15-Cal Ca-sequester Ca-sequester Ca-sequester Ca-sequester Ca-sequester Products: Ca20-Cal
	There are actually 5 Ca-sequester substrates for this reaction, along with Ca15-Cal. Due to system limitations only four are entered.
8	Ca25-bind-Cal	CaRegulation Pathway No. 149	0.0005 (uM^-5 s^-1)	1 (s^-1)	-	-	Substrate: Ca-sequester Ca-sequester Ca-sequester Ca-sequester Ca-sequester Ca20-Cal Products: Ca25-Cal
	There are actually 5 Ca-sequester substrates for this reaction, along with Ca20-Cal. Due to system limitations only four are entered.
9	Ca30-bind-Cal	CaRegulation Pathway No. 149	0.0005 (uM^-5 s^-1)	1 (s^-1)	-	-	Substrate: Ca25-Cal Ca-sequester Ca-sequester Ca-sequester Ca-sequester Ca-sequester Products: Ca30-Cal
	There are actually 5 Ca-sequester substrates for this reaction, along with Ca25-Cal. Due to system limitations only four are entered.
10	Ca35-bind-Cal	CaRegulation Pathway No. 149	0.0005 (uM^-5 s^-1)	1 (s^-1)	-	-	Substrate: Ca-sequester Ca-sequester Ca-sequester Ca-sequester Ca-sequester Ca30-Cal Products: Ca35-Cal
	There are actually 5 Ca-sequester substrates for this reaction, along with Ca30-Cal. Due to system limitations only four are entered.
11	Ca40-bind-Cal	CaRegulation Pathway No. 149	0.0005 (uM^-5 s^-1)	1 (s^-1)	-	-	Substrate: Ca-sequester Ca-sequester Ca-sequester Ca-sequester Ca-sequester Ca35-Cal Products: Ca40-Cal
	There are actually 5 Ca-sequester substrates for this reaction, along with Ca35-Cal. Due to system limitations only four are entered.
12	CaTraspATPase	CaRegulation Pathway No. 149	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 pg200 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

** 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

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