5′-Methylthioadenosine Explained

5′-Methylthioadenosine is S-methyl derivative of the adenosine. It is an intermediate in the methylthioadenosine (MTA) cycle, also known as the methionine salvage pathway that is universal to aerobic life.^{[1] [2]}

Formation

The pervasive cofactor S-adenosyl methionine (SAM) is the precursor to 5′-methylthioadenosine. The sulfonium group in SAM can cleave in three ways, one involves loss of CH₂CH₂CH(NH₃⁺)CO₂⁻, generating the title compound.

History

In 1912, an adenine nucleoside was isolated by Hunter et al. from yeast that were grown without phosphorus or sulfur.^[3] Later in 1925, that substance was shown by Levene and Sobotkal to be adenylthiomethylpentose.^[4]

In 1936, Nakahara et al. did experiments on rats that suggested that vitamin L₂ deficiency inhibits the ability of female rats for lactation.^[5] In 1942, they identified vitamin L₂ to be adenylthiomethylpentose.^[6] Later studies by Folley et al (1942) refuted Nakahara's claims and demonstrated that L2 is not necessary for lactation and thus L₂ is not considered a vitamin today.^[7]

Hecht found in 1937 that the body temperature of rabbits, cats and guinea pigs were lowered by 1 to 2 degrees after he gave them adenylthiomethylpentose at a dose of 0.2 g/kg. Kühn et al. replicated this in guinea pigs in 1941.^[8]

Further reading

• 10.1038/167238a0. Structure of adenylthiomethylpentose. Nature. 167. 4241. 238. 1951. Satoh. Kiyoo. Makino. Katashi. 14806444. 1951Natur.167..238S. free. Formerly known as vitamin L₂.
• Web site: Anthranilic acid (vitamin L) . Davidson . Michael W. . 2018. Formerly known as vitamin L₁.

Notes and References

1. Sekowska . A . Ashida . H . Danchin . A . Revisiting the methionine salvage pathway and its paralogues. . Microbial Biotechnology . January 2019 . 12 . 1 . 77–97 . 10.1111/1751-7915.13324 . 30306718 . 6302742.
2. 10.1111/j.1365-2958.2010.07455.x. Methylthioadenosine/S-adenosylhomocysteine nucleosidase, a critical enzyme for bacterial metabolism. 2011. Parveen. Nikhat. Cornell. Kenneth A.. Molecular Microbiology. 79. 1. 7–20. 21166890. 3057356.
3. J. A. Mandel u. E. K. Dunham . J. Biol. Chem. . 11 . Preliminary note on a purine-hexose compound . 85–86 . 1912. 10.1016/S0021-9258(18)88777-4 . free .
4. P. A. Levene u. H. Sobotka . The thio-sugar from yeast . J. Biol. Chem. . 65 . 551–554 . 1925 . 2 . 10.1016/S0021-9258(18)84864-5 . free .
5. Proceedings of the Imperial Academy . 12 . 1936 . 9 . 289–291 . 10.2183/pjab1912.12.289 . Factor L2, a Second Dietary Factor for Lactation . Waro Nakahara . Fumito Inukai . Saburo Ugami . free .
6. Adenylthiomethylpentose as a Form of Vitamin L₂ . Waro Nakahara . Fumito Inukai . Saburo Ugami . Proceedings of the Imperial Academy . 18 . 8 . 477–478 . 1942. 10.2183/pjab1912.18.477 . free .
7. Nature . 150 . 3802 . 318 . 1942 . 10.1038/150318a0 . Lactation and Reproduction on Highly Purified Diets . S. J. Folley . K. M. Henry . S. K. Kon . 1942Natur.150Q.318F . free .
8. Biological Chemistry . Über die Senkung der Körpertemperatur durch Adenylthiomethylpentose . R. Kuhn u. K. Henkel . 269 . 1 . 1941. 10.1515/bchm2.1941.269.1.41 . 41–46.