Arsenobetaine is an organoarsenic compound

Organoarsenic compound

Organoarsenic chemistry is the chemistry of compounds containing a chemical bond between arsenic and carbon. A few organoarsenic compounds, also called "organoarsenicals," are produced industrially with uses as insecticides, herbicides, and fungicides. In general these applications are declining in...

 that is the main source of arsenic

Arsenic

Arsenic is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. It was first documented by Albertus Magnus in 1250.Arsenic is a metalloid...

 found in fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

. It is the arsenic analog of trimethylglycine

Trimethylglycine

Trimethylglycine is an organic compound that occurs in plants as either glycine betaine or a choline-containing glycine betaine compound. Trimethylglycine was the first betaine discovered by science; originally it was simply called betaine because, in the 19th century, it was discovered in sugar...

, commonly known as betaine. The biochemistry and its biosynthesis

Biosynthesis

Biosynthesis is an enzyme-catalyzed process in cells of living organisms by which substrates are converted to more complex products. The biosynthesis process often consists of several enzymatic steps in which the product of one step is used as substrate in the following step...

 are similar to those of choline

Choline

Choline is a water-soluble essential nutrient. It is usually grouped within the B-complex vitamins. Choline generally refers to the various quaternary ammonium salts containing the N,N,N-trimethylethanolammonium cation....

 and betaine.

Arsenobetaine is a common substance in marine biological systems and unlike many other organoarsenic compounds, such as dimethylarsine and trimethylarsine

Trimethylarsine

Trimethylarsine is the chemical compound with the formula 3As, commonly abbreviated AsMe3 or TMAs. This organic derivative of arsine has been used as a source of arsenic in microelectronics industry, a building block to other organoarsenic compounds, and serves as a ligand in coordination...

, it is relatively non-toxic.

It has been known since 1920 that marine fish contain organoarsenic compounds, but it was not until 1977 that the chemical structure of the most predominant compound arsenobetaine was determined.