Arsenobetaine is an organoarsenic compound that is the main source of arsenic found in fish.[1][2][3][4] It is the arsenic analog of trimethylglycine, commonly known as betaine. The biochemistry and its biosynthesis are similar to those of choline and betaine.

Structural formula of arsenobetaine
Ball-and-stick model of arsenobetaine
Preferred IUPAC name
3D model (JSmol)
ECHA InfoCard 100.162.654 Edit this at Wikidata
EC Number
  • 634-697-3
MeSH Arsenobetaine
RTECS number
  • CH9750000
  • InChI=1S/C5H11AsO2/c1-6(2,3)4-5(7)8/h4H2,1-3H3 ☒N
  • InChI=1/C5H11AsO2/c1-6(2,3)4-5(7)8/h4H2,1-3H3
  • C[As+](C)(C)CC(=O)[O-]
  • C[As+](C)(C)CC([O-])=O
Molar mass 177.997501013 g mol−1
GHS pictograms GHS06: ToxicGHS09: Environmental hazard
GHS Signal word Danger
H301, H331, H400, H410
P261, P264, P270, P271, P273, P301+310, P304+340, P311, P321, P330, P391, P403+233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Arsenobetaine is a common substance in marine biological systems and unlike many other organoarsenic compounds, such as trimethylarsine, it is relatively non-toxic.[5]

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.[6]


Whereas arsenous acid (As(OH)3) has an LD50 (mice) of 34.5 mg/kg (mice), the LD50 for the arsenobetaine exceeds 10 g/kg.[7]


  1. ^ Maher, B. (2005). "Foreword: Research Front — Arsenic Biogeochemistry". Environmental Chemistry. 2 (3): 139–140. doi:10.1071/EN05063.
  2. ^ Francesconi, K. A. (2005). "Current Perspectives in Arsenic Environmental and Biological Research". Environmental Chemistry. 2 (3): 141–145. doi:10.1071/EN05042.
  3. ^ Adair, B. M.; Waters, S. B.; Devesa, V.; Drobna, Z.; Styblo, M.; Thomas, D. J. (2005). "Commonalities in Metabolism of Arsenicals". Environmental Chemistry. 2 (3): 161–166. doi:10.1071/EN05054.
  4. ^ Ng, J. C. (2005). "Environmental Contamination of Arsenic and its Toxicological Impact on Humans". Environmental Chemistry. 2 (3): 146–160. doi:10.1071/EN05062.
  5. ^ Bhattacharya, P.; Welch, A. H.; Stollenwerk, K. G.; McLaughlin, M. J.; Bundschuh, J.; Panaullah, G. (2007). "Arsenic in the Environment: Biology and Chemistry". Science of the Total Environment. 379 (2–3): 109–120. doi:10.1016/j.scitotenv.2007.02.037. PMID 17434206.
  6. ^ Edmonds, J. S.; Francesconi, K. A.; Cannon, J. R.; Raston, C. L.; Skelton, B. W.; White, A. H. (1977). "Isolation, Crystal Structure and Synthesis of Arsenobetaine, the Arsenical Constituent of the Western Rock Lobster Panulirus longipes cygnus George". Tetrahedron Letters. 18 (18): 1543–1546. doi:10.1016/S0040-4039(01)93098-9.
  7. ^ Cullen, William R.; Reimer, Kenneth J. (1989). "Arsenic speciation in the environment". Chemical Reviews. 89 (4): 713–764. doi:10.1021/cr00094a002. hdl:10214/2162.

Further readingEdit