organic sulfur compounds

Organic sulfur compounds, which represent an important subclass of organic substances, are known for their varied occurrence and unusual properties. They occur in such diverse locations as interstellar space, the hot, acidic volcanic areas, and the oceanic depths, as well as the home garden. Organosulfur compounds occur in the bodies of all living creatures n the form of certain essential amino acids—cysteine, cystine, glutathione, and methionine, which are components of proteins—and enzymes, coenzymes, vitamins, and hormones. Typical organisms contain 2 percent sulfur dry weight. A few of the numerous important natural sulfur-containing compounds are Coenzyme A (CoA), biotin, thiamin chloride (vitamin B1), a -lipoic acid, insulin, oxytocin, sulfated polysaccharides, and the nitrogen-fixing nitrogenase enzymes. Certain simple organosulfur compounds, such as thiols, are repugnant to humans and most higher animals even at extraordinarily low concentrations. Employed as defensive secretions by a variety of animal species, thiols figure in unpleasant odors associated with polluted air and water, particularly that resulting from the use of sulfur-rich fossil fuels. On the other hand, related types of organosulfur compounds found in such foods as garlic, onion, chive, leek, cabbage, radish, asparagus, mushrooms, mustard, truffles, coffee, and pineapple are sources of culinary pleasures. Mustard gas [bis( b -chloroethyl) sulfide, (ClCH2CH2)2S] is a potent chemical warfare agent, while other sulfur compounds such as sulfanilamide (a sulfa drug) and penicillin are valued antibiotics. Among the many synthetic organosulfur compounds are inert polymers used in astronauts' transparent face shields, materials possessing the metal-like ability to conduct electricity, agricultural chemicals, insecticides, organic solvents—such as dimethyl sulfoxide, CH3S(=O)CH3, and carbon disulfide, CS2—dyes, lubricating oil constituents, food additives, and substances used to make rayon. Organosulfur compounds are valued reagents widely used for synthesizing new compounds. In the global sulfur cycle, natural organosulfur compounds are interconverted with either inorganic sulfide or sulfate ions. Sulfide or sulfate ions can also be formed in nature from elemental sulfur. Thiols, sulfur analogs of alcohols, are sometimes referred to as mercaptans, for their ability to capture or "seize" mercury.