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Betaine

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This is an old revision of this page, as edited by SunTzuWarmaster (talk | contribs) at 20:41, 26 August 2021 (Hey sorry - I didn't see that the 'food additive' block was added and referenced the dosages for supplementation. Regardless - the "its not safe" line ought be removed from this section considering the above section gives safe dosing guidelines; conflicting. Looks good now.). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

This article is about a class of compounds. For the specific chemical glycine betaine, see trimethylglycine.

A betaine (/ˈbiːtə.iːn, bɪˈteɪ-, -ɪn/) in chemistry is any neutral chemical compound with a positively charged cationic functional group, such as a quaternary ammonium or phosphonium cation (generally: onium ions) that bears no hydrogen atom and with a negatively charged functional group such as a carboxylate group that may not be adjacent to the cationic site.[1] It is a modified amino acid consisting of glycine with three methyl groups serving as methyl donor for various metabolic pathways.[2] Historically, the term was reserved for trimethylglycine (TMG) which is involved in methylation reactions and detoxification of homocysteine.[1]

The pronunciation of the compound reflects its origin and first isolation from sugar beets (Beta vulgaris subsp. vulgaris), and does not derive from the Greek letter beta (β). It is commonly pronounced beta-INE or BEE-tayn.[3]

In biological systems, many naturally occurring betaines serve as organic osmolytes.[citation needed] These are substances synthesized or taken up from the environment by cells for protection against osmotic stress, drought, high salinity, or high temperature. Intracellular accumulation of betaines permits water retention in cells, thus protecting from the effects of dehydration.[citation needed] This accumulation is non-perturbing to enzyme function, protein structure, and membrane integrity. Betaine is also a methyl donor of increasingly recognised significance in biology.[2][1]

Glycine betaine

The chemical structure of trimethylglycine
Main article: Trimethylglycine

The original betaine, N,N,N-trimethylglycine, was named after its discovery in sugar beet (Beta vulgaris subsp. vulgaris) in the nineteenth century.[4] It is a small N-trimethylated amino acid. It is a zwitterion, which cannot isomerize because there is no labile hydrogen atom attached to the nitrogen atom. This substance may be called glycine betaine to distinguish it from other betaines.

Uses

Biochemistry

Phosphonium betaines are intermediates in the Wittig reaction. The addition of betaine to polymerase chain reactions improves the amplification of DNA by reducing the formation of secondary structure in GC-rich regions. The addition of betaine may enhance the specificity of the polymerase chain reaction by eliminating the base pair composition dependence of DNA melting.[5][6]

Food additive

In 2017, the European Food Safety Authority concluded that betaine was safe "as a novel food to be used at a maximum intake level of 6 mg/kg body weight per day in addition to the intake from the background diet."[7]

Approved drug

A prescription drug (Cystadane) containing betaine has limited use for treatment of genetic homocystinuria to lower levels of homocysteine in circulating blood.[2][1]

Dietary supplement

Trimethylglycine, a betaine, is used as a dietary supplement[8].

Safety concern

Betaine is an irritant of eyes and skin.[1]

See also

References

  1. ^ a b c d e "Betaine". PubChem, US National Library of Medicine. 21 August 2021. Retrieved 26 August 2021.
  2. ^ a b c "Betaine". LiverTox, US National Library of Medicine. 26 September 2017. Retrieved 26 August 2021.
  3. ^ Alex Nickon and Ernest F. Silversmith (1987). Organic Chemistry, the Name Game: Modern Coined Terms and Their Origins. Pergamon. ISBN 978-0080344812.
  4. ^ DNA Methylation and Complex Human Disease, Michel Neidhart
  5. ^ Rees, William A.; Yager, Thomas D.; Korte, John; Von Hippel, Peter H. (1993). "Betaine can eliminate the base pair composition dependence of DNA melting". Biochemistry. 32 (1): 137–44. doi:10.1021/bi00052a019. PMID 8418834.
  6. ^ Henke, W; Herdel, K; Jung, K; Schnorr, D; Loening, SA (1997). "Betaine improves the PCR amplification of GC-rich DNA sequences". Nucleic Acids Research. 25 (19): 3957–8. doi:10.1093/nar/25.19.3957. PMC 146979. PMID 9380524.
  7. ^ EFSA Panel on Nutrition, Novel Foods and Food Allergens (5 April 2019). "Safety of betaine as a novel food pursuant to Regulation (EU) 2015/2283". EFSA Journal. doi:10.2903/j.efsa.2019.5658. Retrieved 26 August 2021.
  8. ^ Van Every, Derrick W.; Plotkin, Daniel L.; Delcastillo, Kenneth; Cholewa, Jason; Schoenfeld, Brad J. (2021-08-01). "Betaine Supplementation: A Critical Review of Its Efficacy for Improving Muscle Strength, Power, and Body Composition". Strength & Conditioning Journal. 43 (4): 53–61. doi:10.1519/SSC.0000000000000622. ISSN 1524-1602.

Further reading

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