|Appearance||white crystalline powder with hygroscopicity and characteristic odor.|
|Melting point||120 to 125 °C (248 to 257 °F; 393 to 398 K)|
Except where noted otherwise, data is given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
|what is: / ?)(|
Dimethylsulfoniopropionate (frequently abbreviated to DMSP), is an organosulfur compound with the formula (CH3)2S+CH2CH2COO−. This zwitterionic metabolite can be found in marine phytoplankton, seaweeds, and some species of terrestrial and aquatic vascular plants. It functions as an osmolyte as well as several other physiological and environmental roles have also been identified. DMSP was first identified in the marine red alga Polysiphonia fastigiata by Frederick Challenger and Margaret Simpson (later Dr. Whitaker) 
In higher plants, DMSP is biosynthesized from S-Methylmethionine. Two intermediates in this conversion are dimethylsulfoniumpropylamine and dimethylsulfoniumpropionaldehyde. In algae, however, the biosynthesis starts with removal of the amino group from Methionine, rather than from S-Methylmethionine.
DMSP is broken down by marine microbes to form two major volatile sulfur products, each with distinct effects on the environment. Its major breakdown product is methanethiol (CH3SH), which is assimilated by bacteria into protein sulfur. Its second volatile breakdown product is dimethyl sulfide (CH3SCH3; DMS). Most DMS in seawater is cleaved from DMSP by the enzyme DMSP-lyase, although many non-marine species of bacteria convert methanethiol to DMS.
DMS is also taken up by marine bacteria, but not as rapidly as methanethiol. Although DMS usually consists of less than 25% of the volatile breakdown products of DMSP, the high reactivity of methanethiol makes the steady-state DMS concentrations in seawater approximately 10 times those of methanethiol (~3 nM vs. ~0.3 nM). Curiously, there have never been any published correlations between the concentrations of DMS and methanethiol. This is probably due to the non-linear abiotic and microbial uptake of methanethiol in seawater, and the comparatively low reactivity of DMS. However, a significant portion of DMS in seawater is oxidized to dimethyl sulfoxide (DMSO).
DMSP has also been implicated in influencing the taste and odour characteristics of various products. For example, although DMSP is odourless and tasteless, it is accumulated at high levels in some marine herbivores or filter feeders. Increased growth rates, vigour and stress resistance among animals cultivated on such diets have been reported. DMS, is responsible for repellent, 'off' tastes and odours that develop in some seafood products because of the action of bacterial DMSP-lyase, which cogenerates acrylate.
- CLAW hypothesis, proposing a feedback loop that operates between ocean ecosystems and the Earth's climate
- Coccolithophore, a group of marine unicellular planktonic photosynthetic algae, producer of DMSP
- Dimethyl sulfide, a breakdown product of DMSP along with methanethiol
- Dimethyl selenide, a selenium analogue of DMS produced by bacteria and phytoplankton
- Emiliania huxleyi, a coccolithophorid producing DMSP
- DeBose, Jennifer L.; Sean C. Lema; Gabrielle A. Nevitt (2008-03-07). "Dimethylsulfoniopropionate as a foraging cue for reef fishes" (abstract). Science 319 (5868): 1356. doi:10.1126/science.1151109. PMID 18323445. Retrieved 2008-03-21.Vila-Costa, Maria; Rafel Simo; Hyakubun Harada; Josep M. Gasol; Doris Slezak; Ronald P. Kiene (2006-10-27). "Dimethylsulfoniopropionate uptake by marine phytoplankton" (abstract). Science 314 (5799): 652–654. doi:10.1126/science.1131043. PMID 17068265. Retrieved 2008-03-21.
- Challenger, Frederick; Margaret Isabel Simpson (2014-07-14). "Studies on biological methylation. Part XII. A precursor of the dimethyl sulphide evolved by Polysiphonia fastigiata. Dimethyl-2-carboxyethylsulphonium hydroxide and its salts." (pdf). Journal of the Chemical Society (London) 1948: 1591–1597. doi:10.1039/JR9480001591. PMID 18101461. Retrieved 2014-07-14.
- Scott D. McNeil, Michael L. Nuccio, and Andrew D. Hanson "Betaines and Related Osmoprotectants. Targets for Metabolic Engineering of Stress Resistance" Plant Physiology, August 1999, Vol. 120, pp. 945–949. doi:10.1104/pp.120.4.945