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Accession Type:
Network

PKA_2003

Shared_Object_
PKA_2003

		PKA
		Molecule
		Reaction

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Reaction List for pathway PKA (Pathway Number 196)

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	Kf	Kb	Kd	tau	Substrate	Product
1	cAMP-bind-site-A 1	kf (uM^-1 s^-1)	110 (s^-1)	Kd(bf) = 1.4667(uM)	-	cAMP2.R2C2 cAMP	cAMP3.R2C2
2	cAMP-bind-site-A 2	kf (uM^-1 s^-1)	32.5 (s^-1)	Kd(bf) = 0.4333(uM)	-	cAMP cAMP3.R2C2	cAMP4.R2C2
3	cAMP-bind-site-B 1	kf (uM^-1 s^-1)	33 (s^-1)	Kd(bf) = 0.6111(uM)	-	R2C2 cAMP	cAMP.R2C2
	Hasler et al (1992 jun) FASEB J. 6(9):2735-41 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 (1981 Mar) Proc Natl Acad Sci U S A 78(3) 1591-1595 have better data. First kf/kb=2.1e7/M = 3.5e-5 (#/cell).Ogreid and Doskeland (1981 Jul 6) FEBS Lett 129(2) 287-292 have figs suggesting time course of complete assoc is < 1 min.
4	cAMP-bind-site-B 2	kf (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 (1981 Mar) Proc Natl Acad Sci U S A 78(3) 1591-1595 have better values. They say that this is cooperative, so the consts are now kf/kb =8.3e-4
5	inhib-PKA	kf (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-C1	kf (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-C2	kf (s^-1)	18 (uM^-1 s^-1)	Kd(cb) = 0.3(uM)	-	cAMP4.R2C	PKA-active cAMP4.R2

Pathway Details Molecule List Enzyme List Reaction List

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