MetaNetX provides a bunch of pre-mapped metabolic models.
To ease model comparison, MetaNetX has developed a resource to unify metabolites and biochemical reactions in the context of metabolic models. This unified namespace is called MetaNetX/MNXref.[2][3][4]
MNXref reconciles chemical compounds by structural similarity and biochemical reaction context. Then reconciles biochemical reactions on the basis of the chemical compound reconciliation in an iterative way. Each reconciled group of chemical compounds, biochemical reactions and cellular compartments is a bag of similar items. MNXref sets a referent for each group.