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Reaction List for pathway PKA (Pathway Number 84) in Accession Synaptic_Network (Accession Number 16) |
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 | 1 | PKA Pathway No. 84 | 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. Smith et al PNAS USA 78:3 1591-1595 1981 say that Ka1 is 2.1e7/M which gives a Kd of 47 nM, Kan = 5e8/M or Kd of 2nM. I prefer numbers from Ogreid and Doskeland Febs Lett 129:2 287-292 1981. Their conditions are more physiological. They have figs suggesting time course of complete assoc is < 1 min. |
| 2 | 2 | PKA Pathway No. 84 | 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 B1. This gives kf/kb = .7e-7M * 1e6 / (6e5^2) : 1/(6e5^2) = 2e-13:2.77e-12 |
| 3 | 1 | PKA Pathway No. 84 | 75 (uM^-1 s^-1) | 110 (s^-1) | Kd(bf) = 1.4667(uM) | - | Substrate: R2C2-cAMP2 cAMP Products: R2C2-cAMP3 | This site has a higher Kd for cAMP. See Ogreid and Doskeland 1982 FEBS Lett 150:1 161-166 |
| 4 | 2 | PKA Pathway No. 84 | 75 (uM^-1 s^-1) | 32.5 (s^-1) | Kd(bf) = 0.4333(uM) | - | Substrate: cAMP R2C2-cAMP3 Products: R2C2-cAMP4 | Cooperativity kicks in, now we have a low Kd for cAMP. |
| 5 | Release-C1 | PKA Pathway No. 84 | 60 (s^-1) | 18 (uM^-1 s^-1) | Kd(cb) = 0.3(uM) | - | Substrate: R2C2-cAMP4 Products: PKA-active R2C-cAMP4 | The complex starts to dissociate and release the catalytic subunit C. This has to be fast, as the activation of PKA by cAMP is also fast. |
| 6 | Release-C2 | PKA Pathway No. 84 | 60 (s^-1) | 18 (uM^-1 s^-1) | Kd(cb) = 0.3(uM) | - | Substrate: R2C-cAMP4 Products: PKA-active R2-cAMP4 | Second catalytic subunit is now released. |
| 7 | inhib-PKA | PKA Pathway No. 84 | 60 (uM^-1 s^-1) | 1 (s^-1) | Kd(bf) = 0.0167(uM) | - | Substrate: PKA-active PKA-inhibitor Products: inhibited-PKA | See Doskeland and Ogreid Int J Biochem 13:1-19. Not clear what the rates are, but the reaction has to be fast and it has to have a pretty high affinity. The exact values are not critical under these conditions. |