5′-Methylthioadenosine

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.

In 1912, an adenine nucleoside was isolated by Hunter et al. from yeast that were grown without phosphorus or sulfur.^[5] Later in 1925, that substance was shown by Levene and Sobotkal to be adenylthiomethylpentose.^[6]

In 1936, Nakahara et al. did experiments on rats that suggested that vitamin L₂ deficiency inhibits the ability of female rats for lactation.^[7] In 1942, they identified vitamin L₂ to be adenylthiomethylpentose.^[8] 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.^[9]

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.^[10]