| |
Reaction
Name | Pathway Name /
Pathway No. | Kf | Kb | Kd | tau | Reagents |
| 1 | cAMP-bind-site-A
1 | PKA
Pathway No. 288 | 75.0006
(uM^-1 s^-1) | 110
(s^-1) | Kd(bf) = 1.4667(uM) | - | Substrate:
R2C2-cAMP2
cAMP
Products:
R2C2-cAMP3
|
| 2 | Ca_stoch_cyt | Shared_Object_
AMPAR_CaMKII_
weak_coupling
Pathway No. 281 | 100
(s^-1) | 100
(s^-1) | Keq = 1(uM) | 0.005sec | Substrate:
Ca_control_cyt
Products:
Ca
|
| 3 | Ca_stoch_PSD | Shared_Object_
AMPAR_CaMKII_
weak_coupling
Pathway No. 281 | 100
(s^-1) | 100
(s^-1) | Keq = 1(uM) | 0.005sec | Substrate:
Ca_control_PSD
Products:
Ca-PSD
|
| 4 | CaM-TR2-bind-Ca | CaM
Pathway No. 283 | 71.999
(uM^-2 s^-1) | 72
(s^-1) | Kd(af) = 1(uM) | - | Substrate:
CaM
Ca
Ca
Products:
CaM-TR2-Ca2
|
| Lets use the fast rate consts here. Since the rates are so different, I am not sure whether the order is relevant. These correspond to the TR2C fragment. We use the Martin et al rates here, plus the Drabicowski binding consts. All are scaled by 3X to cell temp. kf = 2e-10 kb = 72 Stemmer & Klee: K1=.9, K2=1.1. Assume 1.0uM for both. kb/kf=3.6e11. If kb=72, kf = 2e-10 (Exactly the same !).... | | 5 | CaM-TR2-bind-Ca-
PSD | CaM
Pathway No. 283 | 72
(uM^-2 s^-1) | 72
(s^-1) | Kd(af) = 1(uM) | - | Substrate:
CaM-PSD
Ca-PSD
Ca-PSD
Products:
CaM-TR2-Ca2-PSD
|
| Lets use the fast rate consts here. Since the rates are so different, I am not sure whether the order is relevant. These correspond to the TR2C fragment. We use the Martin et al rates here, plus the Drabicowski binding consts. All are scaled by 3X to cell temp. kf = 2e-10 kb = 72 Stemmer & Klee: K1=.9, K2=1.1. Assume 1.0uM for both. kb/kf=3.6e11. If kb=72, kf = 2e-10 (Exactly the same !).... | | 6 | equilib | Shared_Object_
AMPAR_CaMKII_
weak_coupling
Pathway No. 281 | 540
(s^-1) | 60
(s^-1) | Not applicable** | - | Substrate:
CaM-Ca4-PSD
Products:
CaM-Ca4
|
| Diffusional equilibrium between PSD- and cytosolic compartment. According to D. Bary in Cell Movements 2nd ed 2001 D for proteins is 5e-7 cm^2/s giving 10 ms for a translocation of 1 um. | | 7 | cAMP-bind-site-B
1 | PKA
Pathway No. 288 | 54
(uM^-1 s^-1) | 33
(s^-1) | Kd(bf) = 0.6111(uM) | - | Substrate:
R2C2
cAMP
Products:
R2C2-cAMP
|
| Hasler et al FASEB J 6:2734-2741 1992 say Kd =1e-7M for type II, 5.6e-8 M for type I. Take mean which comes to 2e-13 #/cell Smith et al PNAS USA 78:3 1591-1595 1981 have better data. First kf/kb=2.1e7/M = 3.5e-5 (#/cell). Ogreid and Doskeland Febs Lett 129:2 287-292 1981 have figs suggesting time course of complete assoc is < 1 min. | | 8 | cAMP-bind-site-B
2 | PKA
Pathway No. 288 | 54
(uM^-1 s^-1) | 33
(s^-1) | Kd(bf) = 0.6111(uM) | - | Substrate:
R2C2-cAMP
cAMP
Products:
R2C2-cAMP2
|
| For now let us set this to the same Km (1e-7M) as site B. This gives kf/kb = .7e-7M * 1e6 / (6e5^2) : 1/(6e5^2) = 2e-13:2.77e-12 Smith et al have better values. They say that this is cooperative, so the consts are now kf/kb =8.3e-4 | | 9 | cAMP-bind-site-A
2 | PKA
Pathway No. 288 | 75.0006
(uM^-1 s^-1) | 32.5
(s^-1) | Kd(bf) = 0.4333(uM) | - | Substrate:
cAMP
R2C2-cAMP3
Products:
R2C2-cAMP4
|
| 10 | Release-C1 | PKA
Pathway No. 288 | 60
(s^-1) | 17.9998
(uM^-1 s^-1) | Kd(cb) = 0.3(uM) | - | Substrate:
R2C2-cAMP4
Products:
PKA-active
R2C-cAMP4
|
| This has to be fast, as the activation of PKA by cAMP is also fast. kf was 10 | | 11 | Release-C2 | PKA
Pathway No. 288 | 60
(s^-1) | 17.9998
(uM^-1 s^-1) | Kd(cb) = 0.3(uM) | - | Substrate:
R2C-cAMP4
Products:
PKA-active
R2-cAMP4
|
| 12 | CaM-TR2-Ca2-bind
-Ca | CaM
Pathway No. 283 | 3.6
(uM^-1 s^-1) | 10
(s^-1) | Kd(bf) = 2.7778(uM) | - | Substrate:
CaM-TR2-Ca2
Ca
Products:
CaM-Ca3
|
| K3 = 21.5, K4 = 2.8. Assuming that the K4 step happens first, we get kb/kf = 2.8 uM = 1.68e6 so kf =6e-6 assuming kb = 10 | | 13 | CaM-TR2-Ca2-bind
-Ca-PSD | CaM
Pathway No. 283 | 3.6
(uM^-1 s^-1) | 10
(s^-1) | Kd(bf) = 2.7778(uM) | - | Substrate:
CaM-TR2-Ca2-PSD
Ca-PSD
Products:
CaM-Ca3-PSD
|
| K3 = 21.5, K4 = 2.8. Assuming that the K4 step happens first, we get kb/kf = 2.8 uM = 1.68e6 so kf =6e-6 assuming kb = 10 | | 14 | CaM-Ca3-bind-Ca-
PSD | CaM
Pathway No. 283 | 0.465
(uM^-1 s^-1) | 10
(s^-1) | Kd(bf) = 21.5048(uM) | - | Substrate:
CaM-Ca3-PSD
Ca-PSD
Products:
CaM-Ca4-PSD
|
| Use K3 = 21.5 uM here from Stemmer and Klee table 3. kb/kf =21.5 * 6e5 so kf = 7.75e-7, kb = 10 | | 15 | CaM-Ca3-bind-Ca | Shared_Object_
AMPAR_CaMKII_
weak_coupling
Pathway No. 281 | 0.465
(uM^-1 s^-1) | 10
(s^-1) | Kd(bf) = 21.5054(uM) | - | Substrate:
CaM-Ca3
Ca
Products:
CaM-Ca4
|
| Use K3 = 21.5 uM here from Stemmer and Klee table 3. kb/kf =21.5 * 6e5 so kf = 7.75e-7, kb = 10 | | 16 | cAMP_diffusion | AC
Pathway No. 289 | 300
(s^-1) | 5.4
(s^-1) | Not applicable** | - | Substrate:
cAMP
Products:
cAMP_in_dend
|
| Represents diffusion, from a volume of 9e-20 to 5e-18. Assuming neck dimensions of 0.1 x 0.1 microns, this works out to a diffusion const of about 270 um^2/sec, which is pretty conservative. It is what cAMP does in frog cilia. | | 17 | CaMKII-bind-CaM | CaMKII
Pathway No. 282 | 49.9997
(uM^-1 s^-1) | 5
(s^-1) | Kd(bf) = 0.1(uM) | - | Substrate:
CaM-Ca4
CaMKII
Products:
CaMKII-CaM
|
| This is tricky. There is some cooperativity here arising from interactions between the subunits of the CAMKII holoenzyme. However, the stoichiometry is 1. Kb/Kf = 6e4 #/cell. Rate is fast (see Hanson et al Neuron 12 943-956 1994) so lets say kb = 10. This gives kf = 1.6667e-4 H&S AnnRev Biochem 92 give tau for dissoc as 0.2 sec at low Ca, 0.4 at high. Low Ca = 100 nM = physiol. | | 18 | CaM_bind_PDE1 | AC
Pathway No. 289 | 719.982
(uM^-1 s^-1) | 5
(s^-1) | Kd(bf) = 0.0069(uM) | - | Substrate:
PDE1
CaM-Ca4
Products:
CaM.PDE1
|
| For olf epi PDE1, affinity is 7 nM. Assume same for brain. Reaction should be pretty fast. Assume kb = 5/sec. Then kf = 5 / (0.007 * 6e5) = 1.2e-3 | | 19 | PKC-stoch-input | Shared_Object_
AMPAR_CaMKII_
weak_coupling
Pathway No. 281 | 2.5
(s^-1) | 2.5
(s^-1) | Keq = 1(uM) | 0.2sec | Substrate:
PKC-control
Products:
PKC-active
|
| 20 | neurogranin-bind
-CaM | CaM
Pathway No. 283 | 0.3
(uM^-1 s^-1) | 1
(s^-1) | Kd(bf) = 3.3333(uM) | - | Substrate:
neurogranin
CaM
Products:
neurogranin-CaM
|
| Surprisingly, no direct info on rates from neurogranin at this time. These rates are based on GAP-43 binding studies. As GAP-43 and neurogranin share near identity in the CaM/PKC binding regions, and also similarity in phosph and dephosph rates, I am borrowing GAP-43 kinetic info. See Alexander et al JBC 262:13 6108-6113 1987 |
and 
color.
