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Table 2 Kinetic parameters (\(\mu \)M,\(\mu \)M/h,/h)

From: Autoreceptor control of serotonin dynamics

Velocity Parameter Model value Literature value References
\(V_{\mathrm{AADC}}\) Aromatic amino acid decarboxylase
\(K_m\) 160 160 [23]
\(V_{max}\) 400   *
\(V_{\mathrm{CATAB}}\) Catabolism of serotonin
\(K_m\) 95 94–95 [24, 25]
\(V_{max}\) 4000   *
\(V_{\mathrm{DRR}}\) Dihydropteridine reductase
\(K_{bh2}\) 100 4–754 [26, 27]
\(K_{\mathrm{NADPH}}\) 75 29–770 [28,29,30]
\(V_{max}^f\) 5000   *
\(K_{bh4}\) 10 1.1–17 [29, 31]
\(K_{\mathrm{NADP}} \) 75 29–770 [28,29,30]
\({V_{max}}^b\) 3   *
\(V_{\mathrm{MAT}}\) Vesicular monoamine transporter
\(K_m\) .2 .123–.253 [32, 33]
\(V_{max}\) 1230   *
\(V_{\mathrm{POOL}}\) Linear exchange between trp and pool
\( k_{topool}\) 9   *
\(k_{frompool} \) 0.6   *
\(V_{\mathrm{SERT}}\) Serotonin transporter
\(K_m\) .06 0.05–1 [34]
\(V_{max}\) 250   *
\(V_{\mathrm{TPH}}\) Tryptophan hydroxylase
\(K_{trp}\) 40 40 [35]
\( K_{bh4}\) 20 20 [35]
\(V_{max} \) 278   *
\(K_i\) (substrate inhibition) 1000 970 [35]
\(V_{trpin}\) Neutral amino acid transporter
\(K_m\) 330 64 [36]
\( V_{max}\) 700   *
\(V_{\mathrm{U2}}\)
  \(K_m\) .17 0.17 [37, 38]
  \(V_{max}\) 14   [37, 38]
Linear diffusion or catabolism
  \(k^{catab}_{trp}\) 2   *
  \(k^{leak}_{cht}\) 1   *
  \(k_{ght}^{leak}\) 1   *
  \(k^{catab}_{hiaa}\) 1 .82 [39]
  \(k^{catab}_{pool}\) 1   *
  \(k_{eht}^{rem}\) 40   *
The serotonin autoreceptor
  \(G_{ht}^{tot}\) 10   *
  \(T_{ht}^{tot}\) 10   *
  \(B_{ht}^{tot}\) 10   *
  \(k_1\) 20   *
  \(k_2\) 200   *
  \(k_3\) 30   *
  \(k_4\) 200   *
  \(k_5\) 36000   *
  \(k_6\) 20000   *
  \(\beta _1\) 1   *
  \(\beta _2\) 1   *
  \(\beta _3\) 1   *
The histamine \(H_3\) receptor
  \(G_{ha}^{tot}\) 1   *
  \(T_{ht}^{tot}\) 60   *
  \(B_{ht}^{tot}\) 10   *
  \(k_{7}\) 4.32   *
  \(k_{8}\) 1.296   *
  \( k_{9}\) 14.4   *
  \( k_{10}\) 25.92   *
  \( k_{11}\) 432   *
  \( k_{12}\) 1440   *
Other constants (varied in some experiments)
  NADP 26   *
  NADPH 330   *
  btrp 96   *
  eha 1.39   *
  1. *See text