<?xml version="1.0" encoding="UTF-8"?>
<sbml xmlns="http://www.sbml.org/sbml/level3/version1/core" level="3" version="1"
      xmlns:comp="http://www.sbml.org/sbml/level3/version1/comp/version1" comp:required="true">

  <model id="aggregate">
    <comp:listOfSubmodels>
      <comp:submodel comp:id="submod1" comp:modelRef="enzyme"/>
      <comp:submodel comp:id="submod2" comp:modelRef="enzyme"/>
    </comp:listOfSubmodels>
  </model>
  <comp:listOfModelDefinitions>
    <comp:modelDefinition id="enzyme" name="enzyme">
      <listOfCompartments>
        <compartment id="compartment" spatialDimensions="3" size="1" constant="true"/>
      </listOfCompartments>
      <listOfSpecies>
        <species id="S"  compartment="compartment" hasOnlySubstanceUnits="false"
                         boundaryCondition="false" constant="false"/>
        <species id="E"  compartment="compartment" hasOnlySubstanceUnits="false" 
                         boundaryCondition="false" constant="false"/>
        <species id="D"  compartment="compartment" hasOnlySubstanceUnits="false" 
                         boundaryCondition="false" constant="false"/>
        <species id="ES" compartment="compartment" hasOnlySubstanceUnits="false"
                         boundaryCondition="false" constant="false"/>
      </listOfSpecies>
      <listOfReactions>
        <reaction id="J0" reversible="true" fast="false">
          <listOfReactants>
            <speciesReference species="S" stoichiometry="1" constant="true"/>
            <speciesReference species="E" stoichiometry="1" constant="true"/>
          </listOfReactants>
          <listOfProducts>
            <speciesReference species="ES" stoichiometry="1" constant="true"/>
          </listOfProducts>
        </reaction>
        <reaction id="J1" reversible="true" fast="false">
          <listOfReactants>
            <speciesReference species="ES" stoichiometry="1" constant="true"/>
          </listOfReactants>
          <listOfProducts>
            <speciesReference species="E" stoichiometry="1" constant="true"/>
            <speciesReference species="D" stoichiometry="1" constant="true"/>
          </listOfProducts>
        </reaction>
      </listOfReactions>
    </comp:modelDefinition>
  </comp:listOfModelDefinitions>
</sbml>