Cysteamine is the chemical compound

Chemical compound

A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 with the formula HSCH₂CH₂NH₂. It is the simplest stable aminothiol and a degradation product of the amino acid

Amino acid

Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

 cysteine

Cysteine

Cysteine is an α-amino acid with the chemical formula HO2CCHCH2SH. It is a non-essential amino acid, which means that it is biosynthesized in humans. Its codons are UGU and UGC. The side chain on cysteine is thiol, which is polar and thus cysteine is usually classified as a hydrophilic amino acid...

. It is often used as the hydrochloride salt, HSCH₂CH₂NH₃Cl.

Biochemical and pharmaceutical applications

Under the trade name Cystagon, cysteamine is used in the treatment of disorders of cystine

Cystine

Cystine is a dimeric amino acid formed by the oxidation of two cysteine residues that covalently link to make a disulfide bond. This organosulfur compound has the formula 2. It is a white solid, and melts at 247-249 °C...

 excretion. Cysteamine cleaves the disulfide bond

Disulfide bond

In chemistry, a disulfide bond is a covalent bond, usually derived by the coupling of two thiol groups. The linkage is also called an SS-bond or disulfide bridge. The overall connectivity is therefore R-S-S-R. The terminology is widely used in biochemistry...

 with cystine

Cystine

Cystine is a dimeric amino acid formed by the oxidation of two cysteine residues that covalently link to make a disulfide bond. This organosulfur compound has the formula 2. It is a white solid, and melts at 247-249 °C...

 to produce molecules that can escape the metabolic defect in cystinosis

Cystinosis

Cystinosis is a lysosomal storage disease characterized by the abnormal accumulation of the amino acid cystine. It is a genetic disorder that typically follows an autosomal recessive inheritance pattern. Cystinosis is the most common cause of Fanconi syndrome in the pediatric age group...

 and cystinuria

Cystinuria

Cystinuria is an inherited autosomal recessive disease that is characterized by the formation of cystine stones in the kidneys, ureter, and bladder.-Signs and symptoms:Cystinuria is a cause of persistent kidney stones...

.

It is also used for treatment of radiation sickness

Radiation Sickness

Radiation Sickness is a VHS by the thrash metal band Nuclear Assault. The video is a recording of a concert at the Hammersmith Odeon, London in 1988. It was released in 1991...

.

Cysteamine is used in the body to form the essential biochemical coenzyme A

Coenzyme A

Coenzyme A is a coenzyme, notable for its role in the synthesis and oxidation of fatty acids, and the oxidation of pyruvate in the citric acid cycle. All sequenced genomes encode enzymes that use coenzyme A as a substrate, and around 4% of cellular enzymes use it as a substrate...

 by combining with pantothenate and adenosine triphosphate

Adenosine triphosphate

Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...

.

In 2008, Raptor Pharmaceuticals started phase II clinical trials testing a delayed release (DR) preparation of cysteamine bitartrate for Huntington's disease

Huntington's disease

Huntington's disease, chorea, or disorder , is a neurodegenerative genetic disorder that affects muscle coordination and leads to cognitive decline and dementia. It typically becomes noticeable in middle age. HD is the most common genetic cause of abnormal involuntary writhing movements called chorea...

. DR Cysteamine is also being investigated as a treatment for cystinosis

Cystinosis

Cystinosis is a lysosomal storage disease characterized by the abnormal accumulation of the amino acid cystine. It is a genetic disorder that typically follows an autosomal recessive inheritance pattern. Cystinosis is the most common cause of Fanconi syndrome in the pediatric age group...

, Batten disease

Batten disease

Batten disease is a rare, fatal autosomal recessive neurodegenerative disorder that begins in childhood...

, and non-alcoholic steatohepatitis.