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Reaction List for pathway Gq (Pathway Number 210) in Accession MAPK_network_2003 (Accession Number 50) |
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 | | Gq Pathway No. 210 | 16.8 (uM^-1 s^-1) | 10 (s^-1) | Kd(bf) = 0.5952(uM) | - | Substrate: mGluR Glu Products: Rec-Glu | kf = kf from text = 1e7 / M / sec = 10 /uM/sec = 10 / 6e5 / # / sec = 1.67e-5 kb = kr from text = 60 / sec Note that we continue to use uM here since [phenylephrine] is also in uM. From Martin et al FEBS Lett 316:2 191-196 1993 we have Kd = 600 nM Assuming kb = 10/sec, we get kf = 10/(0.6 uM * 6e5) = 2.8e-5 1/sec/# |
| 2 | Basal-Act-G | Gq Pathway No. 210 | 0.0001 (s^-1) | 0 (uM^-1 s^-1) | - | - | Substrate: G-GDP Products: G*GTP BetaGamma | kf = kg1 = 0.01/sec, kb = 0. This is the basal exchange of GTP for GDP. |
| 3 | Trimerize-G | Gq Pathway No. 210 | 6 (uM^-1 s^-1) | 0 (s^-1) | - | - | Substrate: G*GDP BetaGamma Products: G-GDP | kf == kg3 = 1e-5 /cell/sec. As usual, there is no back-reaction kb = 0 |
| 4 | Inact-G | Gq Pathway No. 210 | 0.0133 (s^-1) | 0 (s^-1) | - | - | Substrate: G*GTP Products: G*GDP | From Berstein et al JBC 267:12 8081-8088 1992, kcat for GTPase activity of Gq is only 0.8/min |
| 5 | Rec-Glu-bind-Gq | Gq Pathway No. 210 | 0.006 (uM^-1 s^-1) | 0.0001 (s^-1) | Kd(bf) = 0.0167(uM) | - | Substrate: G-GDP Rec-Glu Products: Rec-Glu-Gq | This is the k1-k2 equivalent for enzyme complex formation in the binding of Rec-Glu to Gq. See Fay et al Biochem 30 5066-5075 1991. kf = 5e-5 which is nearly the same as calculated by Fay et al. (4.67e-5) kb = .04 June 1996: Closer reading of Fay et al suggests that kb <= 0.0001, so kf = 1e-8 by detailed balance. This reaction appears to be neglible. |
| 6 | Glu-bind-Rec-Gq | Gq Pathway No. 210 | 16.8 (uM^-1 s^-1) | 0.1 (s^-1) | Kd(bf) = 0.006(uM) | - | Substrate: Glu Rec-Gq Products: Rec-Glu-Gq | From Fay et al kb3 = kb = 1.06e-3 which is rather slow. k+1 = kf = 2.8e7 /M/sec= 4.67e-5/sec use 5e-5. However, the Kd from Martin et al may be more appropriate, as this is Glu not the system from Fay. kf = 2.8e-5, kb = 10 Let us compromise. since we have the Fay model, keep kf = k+1 = 2.8e-5. But kb (k-3) is .01 * k-1 from Fay. Scaling by .01, kb = .01 * 10 = 0.1 |
| 7 | Activate-Gq | Gq Pathway No. 210 | 0.01 (s^-1) | 0 (uM^-2 s^-1) | - | - | Substrate: Rec-Glu-Gq Products: G*GTP BetaGamma Rec-Glu | This is the kcat==k3 stage of the Rec-Glu ezymatic activation of Gq. From Berstein et al actiation is at .35 - 0.7/min From Fay et al Biochem 30 5066-5075 1991 kf = .01/sec From Nakamura et al J physiol Lond 474:1 35-41 1994 see time courses. Also (Berstein) 15-40% of gprot is in GTP-bound form on stim. |
| 8 | Rec-bind-Gq | Gq Pathway No. 210 | 0.6 (uM^-1 s^-1) | 1 (s^-1) | Kd(bf) = 1.6667(uM) | - | Substrate: G-GDP mGluR Products: Rec-Gq | Lets try out the same kinetics as the Rec-Glu-bind-Gq This is much too forward. We know that the steady-state amount of Rec-Gq should be 40% of the total amount of receptor. This is for a different receptor, still we can try to match the value. kf = 1e-6 and kb = 1 give 0.333:0.8 which is pretty close. |
| 9 | q | Gq Pathway No. 210 | 60 (uM^-1 s^-1) | 0.01 (s^-1) | Kd(bf) = 0.0002(uM) | - | Substrate: Rec-Gq mGluRAntag Products: Blocked-rec-Gq | The rate consts give a total binding affinity of only |