Serine out

This reaction describes the utilization of the endproduct Serine in other pathways.

Reaction equation

$Serine \leftrightarrow Serine_{out}$

Rate equation

Simple reversible mass action rate law is used.

$v = K_{1} * [Serine] - K_{2} * [Serine_{out}]$

Parameters

• For Transport reactions it is presumed to be at equilibrium, such that $K_{eq} = 1$ and $K_{1} = K_{2}$.

Parameter	Value	Units	Organism	Remarks
$K_{1}$	0.0103	$S^{-1}$	Escherichia coli
$K_{2}$	0.0103	$S^{-1}$

Parameters with uncertainty

• The transport rates have been modelled using mass action kinetics (i.e., as non-saturable, non-enzymatic reactions). No information is available about the uncertainty of these parameters. As these parameters are strictly positive, they are sampled using a log-normal distribution as are and values. The means of $K_{1}$ are set to the value reported in Turnaev (2006) et al. for the fixed-parameter model. The reaction is presumed to be at equilibrium, such that $K_{eq} = 1$ and $K_{1} = K_{2}$. The sampling of the parameters are done in a way so that it ranges between $[0.001\times mean \quad 1000 \times mean ]$ to allow a large exploration of the parameter space. We use the Range rule to calculate the mean and standard deviation from maximum and minimum value. For both $K_{1}$ and $K_{2}$ the minimum and maximum value lies between 0.0000103 and 10.3. So the mean is 5.16 and standard deviation would be 2.57499.

Parameter	Value	Organism	Remarks
$K_{1}$	$5.16 \pm 2.57$
$K_{2}$	$5.16 \pm 2.57$