Simplified class structure and mapping from KGML to SBML. This mapping includes the SBML qualitative models (qual) and groups extension packages. Most properties are encoded as attributes on the actual classes. Tables 1 and 2 give further details about translation of entries and relations. SBML can only handle reactions. Therefore, SBML-qual is required to properly encode relations. This extension package requires its own model. Subsequently, the SBML-core model and each species have to be duplicated to obtain a qualitativeModel including the translated relations. Furthermore, the groups extension package can be used for a proper encoding of groups in SBML.