The model contains one compartment called C. There are three species called S1, S2 and S3 and five parameters called k1, k2, k3, k4 and p1. The model contains two reactions defined as:
Reaction | Rate |
S1 + S2 → S3 | k1 · S1 · S2 · C |
S3 → S1 + S2 | k2 · S3 · C |
The model contains one event that assigns a value to species S2:
Trigger | Delay | Assignments | |
Event1 | S1 < 0.5 | − | S2 = add(k3, k4) |
The model contains one initialAssignment:
Variable | Formula |
S1 | add(p1, p1) |
Note: SBML's InitialAssignment construct override any declared initial values. In this case the initial value declared for species S1 is inconsistent with the value returned by the InitialAssignment.
Both the eventAssignment and the initialAssignment use the functionDefinition defined as:
Id | Arguments | Formula |
add | x, y | x + y |
The initial conditions are as follows:
Value | Units | |
Initial amount of S1 | 5.0 | mole |
Initial amount of S2 | 2.0 | mole |
Initial amount of S3 | 1.0 | mole |
Value of parameter k1 | 0.75 | litre mole-1 second-1 |
Value of parameter k2 | 0.25 | second-1 |
Value of parameter k3 | 0.8 | mole litre-1 |
Value of parameter k4 | 0.2 | mole litre-1 |
Value of parameter p1 | 0.5 | mole |
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.