Cystine is a naturally occurring, nonessential amino acid that is derived from the amino acid cysteine. It is an important component of proteins and plays a crucial role in maintaining the structure and function of various proteins and enzymes in the body.
In its pure form, cystine is a colorless, crystalline substance that is insoluble in water. It is formed when two cysteine molecules combine and oxidation occurs, resulting in the formation of a disulfide bond between the two cysteine molecules.
Cystine is typically found in high concentrations in animal proteins, such as meat, eggs, and dairy products. It is also present in certain plant-based foods, such as broccoli, Brussels sprouts, and garlic. In the body, cystine is primarily utilized for the synthesis of collagen, a protein that is essential for maintaining the integrity of connective tissues, skin, cartilage, and bones.
Cystine is not only important for protein synthesis but also functions as an antioxidant, helping to neutralize harmful free radicals and protect cells from oxidative damage. It is also involved in the transport of essential minerals, such as zinc and copper, throughout the body.
Although cystine is not considered an essential amino acid since it can be synthesized in the body from methionine and homocysteine, certain individuals with inherited disorders may have difficulty metabolizing cystine properly, leading to the formation of cystine kidney stones.
