Chemical Methylation of Inorganic Mercury with Methylcobalamin, a Vitamin B ₁₂ Analog

Abstract

Chemical methylation of mercuric chloride with methylcobalamin has been studied. Methylated mercury was detected by gas chromatography; and analysis of the products of the reaction by thin-layer chromatography revealed that the methylation proceeded at a remarkably high rate when methylcobalamin and inorganic mercury were mixed. Dimethylmercury was an initial product of the reaction.

Mercury as a global pollutant

“…One of the earliest and best-known examples of environmental mercury poisoning occurred in Japan in 1953 with the first reported cases of « Minamata disease » [1]. Despite the recognition of the toxicity of mercury and mercury vapour in the 17 th century in the Almadén (Spain) mercury mines, Minamata was the first identified example of the in situ methylation and bioaccumulation of mercury in fish.…”

Investigations into the role of methylcobalamin and glutathione for the methylation of antimony using isotopically enriched antimony(V)

“…17 -20 It has also been demonstrated that arsenite methylation by CH 3 -B 12 and glutathione in vitro does not require an enzyme. 20,21 These groups also reported the enhancement of the abiotic arsenic methylation by the addition of selenium(IV).…”

“…There have been a number of reports suggesting a connection between CH 3 -B 12 and arsenite methylation. McBride and Wolfe 13 studied whether CH 3 -B 12 functioned as the methyl donor in the biosynthesis of dimethylarsine from arsenate or arsenite in cell extracts of a certain methanogenic Archaea.…”

“…McBride and Wolfe 13 studied whether CH 3 -B 12 functioned as the methyl donor in the biosynthesis of dimethylarsine from arsenate or arsenite in cell extracts of a certain methanogenic Archaea. Buchet and Lauwerys 14 indicated that CH 3 -B 12 can methylate arsenite at a low rate in the presence and absence of rat liver cytosol.…”

Simultaneous determination of thimerosal and aluminum in vaccines and pharmaceuticals with the use of HPLC method

“…The degradation of thimerosal (TM) involves creation of ethylmercury cation (CH 3 CH 2 Hg + ) [6][7][8][9][10]. Further metabolism of EtHg + intermediate in-cludes stage of dealkylation to inorganic form of mercury Hg 2+ ion [11,12], which can be followed by its methylation to methylmercury form with B12 participation [13][14][15]. Mercury and its organic and inorganic forms are well recognized as the highly toxic substances [16,17] for which the primary target is the central nervous system [18][19][20][21].…”