title: Temperature- and concentration-dependence of compatibility of the organic osmolyte beta-dimethylsulfoniopropionate.
abstract: The effects of the organic osmolyte beta-dimethylsulfoniopropionate (DMSP) on the structural stability of three model proteins were examined to determine whether DMSP, like the structurally similar solute dimethyl sulfoxide (DMSO), is compatible with native protein structure at low, but not elevated, temperatures. DMSP stabilized phosphofructokinase under conditions of cold-induced denaturation. Thus, DMSP, like DMSO, may be an effective protein cryoprotectant. However, DMSP was not an effective stabilizer of protein structure under conditions of heat denaturation. Whereas low (0.2 M) concentrations of DMSP stabilized lactate dehydrogenase against inactivation at 50 degrees C, higher DMSP concentrations were ineffective. DMSP favored the denaturation of glutamate dehydrogenase at all DMSP concentrations tested. DMSP may be a compatible osmotic solute only under conditions of moderate temperature and low, yet physiological, concentrations. The mechanistic basis of DMSP's temperature- and concentration-dependent effects and the possible roles played by adaptation temperature and severity of osmotic stress in the evolutionary selection of organic osmolytes are discussed.
authors.affiliation: Marine Biology Research Division, Scripps Institution of Oceanography, University of California, La Jolla 92093-0202.
authors.forename: M K
authors.initials: MK
authors.lastname: Nishiguchi
authors.forename: G N
authors.initials: GN
authors.lastname: Somero
mesh_terms: D004121:Dimethyl Sulfoxide / Q000031:analogs & derivatives* / Q000494:pharmacology; D004355:Drug Stability; D005969:Glutamate Dehydrogenase / Q000737:chemistry / Q000187:drug effects; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000737:chemistry / Q000187:drug effects; D015394:Molecular Structure; D009994:Osmolar Concentration; D009995:Osmosis; D010732:Phosphofructokinase-1 / Q000037:antagonists & inhibitors / Q000187:drug effects; D011422:Propionates / Q000494:pharmacology*; D011489:Protein Denaturation / Q000187:drug effects; D011506:Proteins / Q000737:chemistry / Q000187:drug effects*; D013452:Sulfonium Compounds / Q000494:pharmacology*; D013696:Temperature
chemical_list: D011422:Propionates; D011506:Proteins; D013452:Sulfonium Compounds; C068078:dimethylpropiothetin; D007770:L-Lactate Dehydrogenase; D005969:Glutamate Dehydrogenase; D010732:Phosphofructokinase-1; D004121:Dimethyl Sulfoxide