Table 1 Parameters and initial conditions for the numerical simulations under healthy conditions.

From: A mathematical model of GLUT1 modulation in rods and RPE and its differential impact in cell metabolism

Parameter

Value

Source

Parameter

Value

Source

G

5 mM

+54

\(\lambda _E\)

0.8 mM\(^{-1}\)

\(\circ\)

\(V_{\mathrm{max}_{[\text{g}_E]}}\)

1.2 mM min\(^{-1}\)

+55

\(\lambda _{LACT_E}\)

480 mM\(^{-1}\)

\(\circ\)

\(K_{m_{[\text{g}_E]}}\)

9 mM

55

\(\lambda _r\)

21.7E−3 mM\(^{-1}\)

\(\circ\)

\(V_{\mathrm{max}_{[\text{G6P}_{E}]}}\)

0.00738 mM min\(^{-1}\)

\(\psi _{[\text{PYR}_E]}\)

710 min\(^{-1}\)

\(\circ\)

\(K_{m_{[\text{G6P}_{E}]}}\)

0.002844 mM

\(\psi _{[\text{NADPH}_r]}\)

15E2 min\(^{-1}\)

+

\(V_{\mathrm{max}_{[\text{g}_r]}}\)

0.8 mM min\(^{-1}\)

55

\(\psi _{[\text{LACT}_r]}\)

96E2 min\(^{-1}\)

\(\circ\)

\(K_{m_{[\text{g}_r]}}\)

8 mM

55

\(\psi _{[\text{G3P}_r]}\)

0.02 min\(^{-1}\)

+

\(V_{\mathrm{max}_{[\text{F16BP}_E]}}\)

1.2285 mM min\(^{-1}\)

\(\diamond\) +56

[GLUT1]

1

\(\circ\)

\(K_{m_{[\text{F16BP}_E]}}\)

0.1106 mM

\(c_{M1}\)

1

\(\circ\)

\(V_{\mathrm{max}_{[\text{PYR}_E]}}\)

0.00783 mM min\(^{-1}\)

\(\delta _r\)

13E8

\(\circ\)

\(K_{m_{[\text{PYR}_E]}}\)

0.17 mM

[PYR\(_E\)*]

4.6E−5 mM

\(\circ\)

\(V_{\mathrm{max}_{[\text{PYR}_rE]}}\)

14 mM min\(^{-1}\)

[PEP*]

1.65E−13 mM

\(\circ\)

\(K_{m_{[\text{PYR}_rE]}}\)

0.125 mM

*

\(q_r\)

0.18

+

\(V_{\mathrm{max}_{[\text{F16BP}_r]}}\)

1.365 mM min\(^{-1}\)

+56

\(\rho _r\)

1E−3

+54

\(K_{m_{[\text{F16BP}_r]}}\)

3.5 mM

+56

[g\(_r\)]\(_0\)

0.1 mM

\(V_{\mathrm{max}_{[\text{G6P}_{r}]}}\)

0.1845 mM min\(^{-1}\)

+57

[G6P\(_r\)]\(_0\)

0.45 mM

+

\(K_{m_{[\text{G6P}_{r}]}}\)

0.09 mM

+54

[F16BP\(_r\)]\(_0\)

0.06 mM

+

\(V_{\mathrm{max}_{[\text{NADPH}_{r}]}}\)

0.228 mM min\(^{-1}\)

+58

[NADPH\(_r\)]\(_0\)

0.1E−8 mM

\(K_{m_{[\text{NADPH}_{r}]}}\)

0.45 mM

+58

[PYR\(_r\)]\(_0\)

0 mM

42

\(V_{\mathrm{max}_{[\text{PYR}_r]}}\)

0.3915 mM min\(^{-1}\)

+57

[LACT\(_r\)]\(_0\)

1E−4 mM

+

\(K_{m_{[\text{PYR}_r]}}\)

0.06 mM

57

[G3P\(_r\)]\(_0\)

2.5E−6 mM

+

\(V_{\mathrm{max}_{[\text{G3P}_r]}}\)

0.15 mM min\(^{-1}\)

+54

[g\(_E\)]\(_0\)

3 mM

+

\(K_{m_{[\text{G3P}_r]}}\)

0.143 mM

+54

[G6P\(_E\)]\(_0\)

5E−3 mM

\(V_{\mathrm{max}_{[\text{LACT}_r]}}\)

0.14 mM min\(^{-1}\)

+

[F16BP\(_E\)]\(_0\)

0.13 mM

\(K_{{m}_[\text{LACT}_r]}\)

1.25E−5 mM

[PYR\(_E\)]\(_0\)

0 mM

42

  1. The parameters marked as (+), are used exactly as they appear in Camacho et al.50, and the reference where they were originally reported is provided when applicable. The parameter marked as (\(\diamond\)) is within \(\pm \,10{\%}\) of the value reported in the provided reference. The parameters marked as (\(\circ\)) are scaling constants added to this model and do not represent any real kinetic or concentration value in the cells. The parameters marked as (−) are estimated for this example by performing a systematic parameter sweep in which their values were changed by a small fraction. This sweep was iterated many times until the responses provided the best qualitative approximation to the available experimental data, as mentioned in “Model validation” section. The value of parameter \(K_{m_{[\text{PYR}_{rE}]}}\) (marked with *) is equal to the value of parameter \(K_{m_{\mathrm{[LACT]}}}\) in50 because the enzyme Lactate dehydrogenase b (LDHB) enables the transformation of pyruvate into lactate, and vice versa.