Workflow for building the cell-specific reconstructions. Human Recon 1  was utilized as the starting point for modeling human metabolism. The genome sequence annotation upon which Recon 1 was built was updated, and all incorrectly lumped and balanced reactions were corrected. Multiple reaction and enzyme databases, including UniProt, were then used to build a draft model. The draft model was then manually curated using literature and multiple high-throughput data sets. In addition, important metabolic pathways that were not in Recon 1 (e.g. hepatic ketogenesis) were added accordingly to the cell-specific reconstructions.