Betaine: Difference between revisions
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===Biochemistry=== |
===Biochemistry=== |
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Phosphonium betaines are intermediates in the [[Wittig reaction]]. The addition of betaine to [[polymerase chain reaction]]s 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.<ref name="Rees et al">{{cite journal |last1=Rees |first1=William A. |last2=Yager |first2=Thomas D. |last3=Korte |first3=John |last4=Von Hippel |first4=Peter H. |title=Betaine can eliminate the base pair composition dependence of DNA melting |journal=Biochemistry |volume=32 |issue=1 |pages=137–44 |year=1993 |pmid=8418834 |doi=10.1021/bi00052a019}}</ref><ref name="Henke et al">{{cite journal |last1=Henke |first1=W |last2=Herdel |first2=K |last3=Jung |first3=K |last4=Schnorr |first4=D |last5=Loening |first5=SA |title=Betaine improves the PCR amplification of GC-rich DNA sequences |journal=Nucleic Acids Research |volume=25 |issue=19 |pages=3957–8 |year=1997 |pmid=9380524 |pmc=146979 |doi=10.1093/nar/25.19.3957}}</ref> |
Phosphonium betaines are intermediates in the [[Wittig reaction]]. The addition of betaine to [[polymerase chain reaction]]s 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.<ref name="Rees et al">{{cite journal |last1=Rees |first1=William A. |last2=Yager |first2=Thomas D. |last3=Korte |first3=John |last4=Von Hippel |first4=Peter H. |title=Betaine can eliminate the base pair composition dependence of DNA melting |journal=Biochemistry |volume=32 |issue=1 |pages=137–44 |year=1993 |pmid=8418834 |doi=10.1021/bi00052a019}}</ref><ref name="Henke et al">{{cite journal |last1=Henke |first1=W |last2=Herdel |first2=K |last3=Jung |first3=K |last4=Schnorr |first4=D |last5=Loening |first5=SA |title=Betaine improves the PCR amplification of GC-rich DNA sequences |journal=Nucleic Acids Research |volume=25 |issue=19 |pages=3957–8 |year=1997 |pmid=9380524 |pmc=146979 |doi=10.1093/nar/25.19.3957}}</ref> |
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===Food additive=== |
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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."<ref name="efsa">{{cite journal |title=Safety of betaine as a novel food pursuant to Regulation (EU) 2015/2283 |journal=EFSA Journal|author=EFSA Panel on Nutrition, Novel Foods and Food Allergens|date=5 April 2019 |doi=10.2903/j.efsa.2019.5658 |url=https://efsa.onlinelibrary.wiley.com/doi/full/10.2903/j.efsa.2019.5658 |access-date=26 August 2021}}</ref> |
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===Approved drug=== |
===Approved drug=== |
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A [[prescription drug]] (''Cystadane'') containing betaine has limited use for treatment of [[genetic]] [[homocystinuria]] to lower levels of [[homocysteine]] in circulating blood.<ref name=livertox/><ref name=pubchem/> |
A [[prescription drug]] (''Cystadane'') containing betaine has limited use for treatment of [[genetic disorder|genetic]] [[homocystinuria]] to lower levels of [[homocysteine]] in circulating blood.<ref name=livertox/><ref name=pubchem/> |
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===Dietary supplement=== |
===Dietary supplement=== |
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Revision as of 20:36, 26 August 2021
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 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] with maximum safe dosing in the EU determined to be 6mg/kg daily[9].
Safety concern
Betaine is an irritant of eyes and skin.[1]
See also
References
- ^ a b c d e "Betaine". PubChem, US National Library of Medicine. 21 August 2021. Retrieved 26 August 2021.
- ^ a b c "Betaine". LiverTox, US National Library of Medicine. 26 September 2017. Retrieved 26 August 2021.
- ^ Alex Nickon and Ernest F. Silversmith (1987). Organic Chemistry, the Name Game: Modern Coined Terms and Their Origins. Pergamon. ISBN 978-0080344812.
- ^ DNA Methylation and Complex Human Disease, Michel Neidhart
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ Turck, Dominique; Castenmiller, Jacqueline; Henauw, Stefaan De; Hirsch-Ernst, Karen Ildico; Kearney, John; Maciuk, Alexandre; Mangelsdorf, Inge; McArdle, Harry J.; Naska, Androniki; Pelaez, Carmen; Pentieva, Kristina (2019). "Safety of betaine as a novel food pursuant to Regulation (EU) 2015/2283". EFSA Journal. 17 (4): e05658. doi:10.2903/j.efsa.2019.5658. ISSN 1831-4732. PMC 7009179. PMID 32626284.
{{cite journal}}: CS1 maint: PMC format (link)
Further reading
- IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "betaines". doi:10.1351/goldbook.B00637
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