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Accession Type:
Network
cAMP_pathway
Shared_Object_
cAMP_pathway
PKA
 Molecule
 Reaction
AC
Gs

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Reaction List for pathway PKA (Pathway Number 135)

Kd is calculated only for second order reactions, like nA+nB <->nC or nA<->nC+nD, where n is number and A,B,C,D are molecules, where as for first order reactions Keq is calculated. Kd for higher order reactions is not considered.
  Name KfKbKdtauSubstrateProduct
1 cAMP-bind-site-A
1
75
(uM^-1 s^-1)
110
(s^-1)
Kd(bf) = 1.4667(uM)-cAMP2.R2C2
cAMP
cAMP3.R2C2
2 cAMP-bind-site-A
2
75
(uM^-1 s^-1)
32.5
(s^-1)
Kd(bf) = 0.4333(uM)-cAMP
cAMP3.R2C2
cAMP4.R2C2
3 cAMP-bind-site-B
1
54
(uM^-1 s^-1)
33
(s^-1)
Kd(bf) = 0.6111(uM)-R2C2
cAMP
cAMP.R2C2
  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.
4 cAMP-bind-site-B
2
54
(uM^-1 s^-1)
33
(s^-1)
Kd(bf) = 0.6111(uM)-cAMP.R2C2
cAMP
cAMP2.R2C2
  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
5 inhib-PKA60
(uM^-1 s^-1)
1
(s^-1)
Kd(bf) = 0.0167(uM)-PKA-active
PKA-inhibitor
inhibited-PKA
  This has to be set to zero for matching the expts in vitro. In vivo we need to consider the inhibition though.
6 Release-C160
(s^-1)
18
(uM^-1 s^-1)
Kd(cb) = 0.3(uM)-cAMP4.R2C2
PKA-active
cAMP4.R2C
  This has to be fast, as the activation of PKA by cAMP is also fast. kf was 10
7 Release-C260
(s^-1)
18
(uM^-1 s^-1)
Kd(cb) = 0.3(uM)-cAMP4.R2C
PKA-active
cAMP4.R2


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