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Reaction Name | Pathway Name / Pathway No. | Kf | Kb | Kd | tau | Reagents |
1 | CaM-TR2-bind-Ca | CaM
Pathway No. 81 | 72 (uM^-2 s^-1) | 72 (s^-1) | Kd(af) = 1(uM) | - | Substrate: CaM Ca Ca
Products: CaM-TR2-Ca2
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| We use the Martin et al 1985 Eur J Biochem 151(3):543-550 rates here, plus the Drabikowski and Brzeska 1982 JBC 257(19):11584-11590 binding consts. All are scaled by 3X to cell temperature. kf = 2e-10 kb = 72 Stemmer & Klee 1994 Biochem 33:6859-6866 have values of : K1=.9, K2=1.1. Assume 1.0uM for both | 2 | CaM-TR2-Ca2-bind -Ca | CaM
Pathway No. 81 | 3.6 (uM^-1 s^-1) | 10 (s^-1) | Kd(bf) = 2.7778(uM) | - | Substrate: CaM-TR2-Ca2 Ca
Products: CaM-Ca3
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| Stemmer and Klee 1994 Biochem 33:6859-6866 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 | 3 | CaM-Ca3-bind-Ca | CaM
Pathway No. 81 | 0.465 (uM^-1 s^-1) | 10 (s^-1) | Kd(bf) = 21.5054(uM) | - | Substrate: CaM-Ca3 Ca
Products: CaM-Ca4
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| Use K3 = 21.5 uM here from Stemmer and Klee table 3. Stemmer and Klee 1994 Biochem 33:6859-6866 kb/kf =21.5 * 6e5 so kf = 7.75e-7, kb = 10 | 4 | neurogranin-bind -CaM | CaM
Pathway No. 81 | 0.3 (uM^-1 s^-1) | 1 (s^-1) | Kd(bf) = 3.3333(uM) | - | Substrate: neurogranin CaM
Products: neurogranin-CaM
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| 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 | 5 | dephosph-neurogr anin | CaM
Pathway No. 81 | 0.005 (s^-1) | 0 (s^-1) | - | - | Substrate: neurogranin*
Products: neurogranin
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| This is put in to keep the basal levels of neurogranin* experimentally reasonable. From various papers, specially Ramakers et al JBC 270:23 1995 13892-13898, it looks like the basal level of phosph is between 20 and 40%. I estimate around 25 % The kf of 0.005 gives around this level at basal PKC activity levels of 0.1 uM active PKC. |