Iduronic acid is a type of sugar molecule known as a uronic acid. It is a component of certain complex carbohydrates, particularly in glycosaminoglycans, which are important for the structure and function of connective tissues in the body. Iduronic acid plays a role in maintaining the elasticity and hydration of tissues. This molecule is found in various biological substances, including heparin and hyaluronic acid. Its unique structure allows it to interact with proteins and other molecules, contributing to various physiological processes. Understanding iduronic acid is important for research in fields like biochemistry and medicine.