The protein-protein interaction network on myocardial metabolism. A. protein-protein interaction network on metabolism was done by downloading pathway data from Kyoto Encyclopedia of Genes and Genomes(KEGG) database, then enzyme-enzyme interaction (ECrel) and protein-protein interaction (PPrel) was analyzed by KEGGSOAP software. Finally, the network of relationship among proteins was built and brought forth by Medusa software. The network was graphically visualized as nodes and edges. Pink lines indicate connections confirmed experimentally by other researches, blue lines indicate connections derived from databases and yellow lines indicate connections compiled from co-citation data from literature mining PubMed abstracts. Interestingly, about 55% of those proteins showing in the network are involved in glycolysis. B. The number of connections of each protein was calculated. ENO1, TPI1 and GAPDH are central "functional hubs" in the map with more connections than other proteins. They are all important glycolytic enzymes in myocardium.