Mercaptans, biological methylation

Biological. After 20 d, methyl mercaptan started to degrade in anaerobic sediments and sludges producing stoichiometric amounts of methane. Complete degradation was achieved after 20 d. Under anaerobic freshwater conditions, methyl mercaptan were degraded by methanogenic archea (van... 

Siibstitution. A modification of the jS-elimination reaction may be substitution of a new group. This has been proposed as the mechanism of action of tryptophan desmolase, in which indole is substituted for the OH of serine. This reaction was found to proceed to a measurable extent in model reactions, in spite of the competing 8-elimination reactions of both serine and tryptophan and other side reactions of indole compounds. Additional substitution reactions of biological significance are the formation of cystathionine from homocysteine and serine and the formation of (Sf-methylcysteine from methyl mercaptan and serine. These reactions are catalyzed by enzymes that require pyridoxal phosphate as a cofactor. 

Methanetiol, CH3SH is also called methyl mercaptan, and its sources are mainly marine biology. The reaction with OH radicals is thought to be the hydrogen abstraction (Atkinson et al. 2004 Sander et al. 2011),... 

Although methyl mercaptan (CH3SH) is of little biological interest in terms of its radioprotective properties, a wealth of experimental information is available and can be used in testing a novel theoretical model to be employed in the subsequent study of cysteamine, an experimentally known radioprotective compound. Among those properties is the ionization energy of the thiol. 

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