 Biochemical pathways are manually curated by SGD and provided using the Pathway Tools browser version 15.0 (13).The SGD biochemical pathways data set for S. cerevisiae, one of the most highly curated data sets among all Pathway Tools data sets available, is the gold standard for budding yeast; SGD supports an ongoing effort to update and enhance these data.The Pathway Tools interface provides a complete description of each pathway, with molecular structures, E.C.