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

Reaction Rate
S1 + S2 → S3 + S4 k1 · S1 · S2 · compartment
S3 + S4 → S1 + S2 k2 · S3 · S4 · compartment

The value of k2 is zero, which means the reverse reaction should occur at zero rate (i.e. not at all).

The initial conditions are as follows:

Value Units
Initial amount of S1 1.0 × 10−4 mole
Initial amount of S2 1.5 × 10−4 mole
Initial amount of S3 2.0 × 10−4 mole
Initial amount of S4 1.0 × 10−4 mole
Value of parameter k1 0.75 × 104 litre mole-1 second-1
Value of parameter k2 0 litre mole-1 second-1
Volume of compartment "compartment" 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.