Biotransformations of selenium by Enterobacter cloacae SLD1a-1:Formation of dimethylselenide

Authors: Dungan R.S.¹; Frankenberger Jr W.T.²

Source: Biogeochemistry, Volume 55, Number 1, August 2001 , pp. 73-86(14)

Publisher: Springer

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Abstract:

Whole-cell suspensions of Enterobacter cloacae SLD1a-1 produced dimethylselenide (DMSe) from selenate, selenite, elemental selenium, dimethylselenone, seleno-DL-methionine, 6-selenoinosine, and 6-selenopurine. Cell-free extracts of the bacterium produced the formation of DMSe from organic selenium compounds, including dimethylselenone, dimethylselenoniopropionate, seleno-DL-methionine, seleno-DL-ethionine, and 6-selenoguanosine. The highest rate of DMSe production occurred from whole-cell suspensions and cell-free extracts containing dimethylselenone. DMSe was also produced by cell-free extracts containing selenite or elemental selenium and methylcobalamin. Cell-free extracts did not produce DMSe from inorganic selenium when S-adenosyl-L-methionine was present. Additionally, DL-homocysteine and L-methionine were found to inhibit selenium volatilization. These findings suggest the formation of DMSe from inorganic selenium occurs through the transfer of a methyl group from methylcobalamin.

Keywords: biomethylation; biotransformations; dimethylselenide; demethylselenone; selenium

Language: English

Document Type: Regular paper

Affiliations: 1: Department of Environmental Sciences, University of California, Riverside CA 92521, U.S.A. 2: Department of Environmental Sciences, University of California, Riverside CA 92521, U.S.A. (Author for correspondence, Fax: +1 (909) 787-2954, e-mail: william.frankenberger@ucr.edu)

Publication date: 2001-08-01