The model contains one compartment called C. There are four species named S1, S2, S3 and S4 and three parameters named k1, k2 and k3. The model contains three reactions defined as:

Reaction Rate
S1 → S2 k1 · S1 · C
S2 → S3 k2 · S2 · C
S3 → S4 k3 · S3 · C

The model contains one initialAssignment:

Variable Formula
k1 0.2 + k2· exp(t)

where the symbol 't' denotes the current simulation time.

Note: SBML's InitialAssignment take effect at time t < 0 and continue to have effect up to and including time t = 0, overriding any initial values. In this model, the initial value for the parameter k1 has not been explicitly declared and must be calculated using the InitialAssignment at time = 0.

The initial conditions are as follows:

Value Units
Initial amount of S1 1.0 × 10−4 mole
Initial amount of S2 0 mole
Initial amount of S3 0 mole
Initial amount of S4 0 mole
Value of parameter k1 undeclared second-2
Value of parameter k2 0.5 second-2
Value of parameter k3 1 second-2
Volume of compartment C 1 litre

The species values are given as amounts of substance to make it easier to use the model in a discrete stochastic simulator, but (as per usual SBML principles) their symbols represent their values in concentration units where they appear in expressions.

Note: The test data for this model was generated from an analytical solution of the system of equations.