Enzymatic sulphur oxygenation reactions

Sulphur is a key constituent in a wide variety of biologically important compounds, ranging from amino acids and coenzymes to antibiotics and pesticides. In analogy with the more widely studied metabolism of aromatic or aliphatic hydrocarbons and amines, the intial step in metabolism of sulphur compounds is commonly oxygenation on sulphur. While sulphur oxygenation in vivo has been known for many years, it is only within the past decade that many of the enzymes responsible have been identified, and molecularlevel details have become available. This review focuses on the molecular aspects of enzymatic sulphur oxygenation, and considers mono and dioxygenases active on inorganic sulphur, organic thiols, thioethers, thioesters and thiones. Information from very diverse areas of the literature is brought together, and the implications of sulphur oxygenation reactions to drug design, as well as to environmental and toxicological areas, are mentioned.