Transformations of Dimethylsulfide - The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment - page 275

2.4.2 Distribution, Genomic Context, and Phylogeny of Dimethylsulfide
Monooxygenases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 304

3 GENERAL CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306

ABBREVIATIONS ............................................................................ 307

ACKNOWLEDGMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308

REFERENCES ................................................................................. 308

Abstract Dimethylsulfide (DMS) is a naturally occurring chemical that is part of the
biogeochemical sulfur cycle and has been implicated in climate-relevant atmospheric
processes. In addition, DMS occurs in soil environments as well as in food stuff as a
flavor compound and it can also be associated with disease states such as halitosis.
A major environmental source of DMS is the marine algal osmoprotectant dimethyl-
sulfoniopropionate (DMSP). A variety of bacterial enzyme systems lead either to the
production of DMS from DMSP or dimethylsulfoxide (DMSO) or its oxidation to,
e.g., DMSO. The interconversion of DMS and DMSO is catalyzed by molybdenum-
containing metalloenzymes that have been very well studied, and recently another
enzyme system, an NADH-dependent, flavin-containing monooxygenase, that

produces formaldehyde and methanethiol from DMS has also been described.
DMS conversions are not limited to a specialized group of bacteria - evidence
for DMS-based metabolism exists for heterotrophic, autotrophic and phototrophic
bacteria and there is also evidence for the occurrence of this type of sulfur
compound conversion in Archaea.

Keywords dimethylsulfide • dimethylsulfoxide • DMS dehydrogenase • DMS
monooxygenase • DMSO reductase

Please cite as: Met. Ions Life Sci . 14 (2014) 279-313

1 Introduction

1.1 Dimethylsulfide - Sources and Sinks in the Biosphere

Dimethylsulfide (CH 3 -S-CH 3 , DMS) is a volatile organic sulfur compound. It is
poorly soluble in water and has a low boiling point of 38 C. Its characteristic odor
may be unpleasant even at relatively low concentrations. Production of DMS can be
the cause of malodorous emissions from a wide range of industries and operations,
for example composting, brewing, animal husbandry, and paper milling, but also
contributes to halitosis (bad breath). At low concentration, DMS has a sweet odor
that is an important part of the aroma of a wide variety of foods and beverages
([ 1 , 2 ] and references therein).
DMS has been the subject of much interest due to its prominent role in the
biogeochemical cycle of sulfur. DMS is the largest biogenic source of sulfur to the
atmosphere and it has been estimated that the annual flux of DMS from the oceans