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Reaction List for pathway PLCbeta (Pathway Number 151) 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	PLC-Gq-bind-Ca	PLCbeta Pathway No. 151	30 (uM^-1 s^-1)	1 (s^-1)	Kd(bf) = 0.0333(uM)	-	Substrate: PLC-Gq Ca Products: PLC-Ca-Gq
	this step has a high affinity for Ca, from Smrcka et al. 0.1uM so kf /kb = 1/6e4 = 1.666e-5:1. See the Act-PLC-by-Gq reaction. Raised kf to 5e-5 based on match to conc-eff curves from Smrcka et al.
2	Act-PLC-by-Gq	PLCbeta Pathway No. 151	25.2 (uM^-1 s^-1)	1 (s^-1)	Kd(bf) = 0.0397(uM)	-	Substrate: PLC-Ca GGTP Products:* PLC-Ca-Gq
	Affinity for Gq is > 20 nM (Smrcka et al Science251 804-807 1991) so [Gq].kf = kb so 40nM * 6e5 = kb/kf = 24e3 so kf = 4.2e-5, kb =1
3	Act-PLC-Ca	PLCbeta Pathway No. 151	3 (uM^-1 s^-1)	1 (s^-1)	Kd(bf) = 0.3333(uM)	-	Substrate: Ca PLC Products: PLC-Ca
	Affinity for Ca = 1uM without AlF, 0.1 with: from Smrcka et al science 251 pp 804-807 1991 so [Ca].kf = kb so kb/kf = 1 * 6e5 = 1/1.66e-6 Assigned affinity to a Kd of 0.333 to maintain balance.
4	PLC-bind-Gq	PLCbeta Pathway No. 151	2.52 (uM^-1 s^-1)	1 (s^-1)	Kd(bf) = 0.3968(uM)	-	Substrate: PLC GGTP Products:* PLC-Gq
	this binding does not produce active PLC. This step was needed to implement the described (Smrcka et al) increase in affinity for Ca by PLC once Gq was bound. The tempkin are the same as the binding step for Ca-PLC to Gq. Kd is constrained by detailed balance.
5	Inact-PLC-Gq	PLCbeta Pathway No. 151	1.6667 (s^-1)	0 (uM^-1 s^-1)	-	-	Substrate: PLC-Ca-Gq Products: PLC-Ca G*GDP
	Rate of 100/min to account for GAP activity of PLC: Biddlecome et al, JBC, 271, 14, 7999-8007, 1996
6	Degrade-DAG	PLCbeta Pathway No. 151	0.15 (s^-1)	0 (s^-1)	-	-	Substrate: DAG Products: PC
	Rate based on basal and activated levels of DAG
7	basal	PLCbeta Pathway No. 151	0.003 (s^-1)	0 (uM^-1 s^-1)	-	-	Substrate: PIP2 Products: DAG IP3(145)
	accounts for other PLC isoforms that contribute to basal levels of IP3

Database compilation and code copyright (C) 2022, Upinder S. Bhalla and NCBS/TIFR
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