Taurine is an amino sulfonic acid that is the 2-amino derivative of ethanesulfonic acid. It is a naturally occurring amino acid derived from methionine and cysteine metabolism. An abundant component of fish- and meat-based foods, it has been used as an oral supplement in the treatment of disorders such as cystic fibrosis and hypertension. It has a role as a human metabolite, an antioxidant, a mouse metabolite, a Saccharomyces cerevisiae metabolite, an Escherichia coli metabolite, a glycine receptor agonist, a nutrient and a radical scavenger. It is a conjugate acid of a 2-aminoethanesulfonate. It is a tautomer of a taurine zwitterion.