Which substance conjugates bilirubin for excretion?

Bilirubin is a byproduct of the breakdown of hemoglobin from red blood cells. Once bilirubin is formed, it is fat-soluble and needs to be transformed into a water-soluble form for excretion from the body. This transformation occurs in the liver, where bilirubin undergoes a process known as conjugation.

The correct substance that conjugates bilirubin is glucuronic acid. During this process, bilirubin combines with glucuronic acid through the action of the enzyme UDP-glucuronosyltransferase. The addition of glucuronic acid makes bilirubin more soluble in water, allowing it to be excreted in bile and subsequently eliminated from the body through the intestines. This conjugated form of bilirubin is also referred to as direct bilirubin, and it plays a crucial role in the body’s ability to remove waste from the breakdown of hemoglobin.

Other substances mentioned have different functions. Sulfate, for instance, is involved in various metabolic processes but does not play a role in bilirubin conjugation. Glutathione serves as an important antioxidant and may participate in detoxification pathways, but it is not directly involved in bilirubin conjugation. Albumin primarily functions as a carrier protein in the