Organic sulfur compounds

Definition

Carbon-based molecules containing covalently bonded sulfur, including thiols, sulfides, disulfides, sulfoxides, and heterocyclic structures such as thiophenes. In arthropod biology, these compounds function prominently as defensive allomones, alarm pheromones, and venom constituents, often conferring strong odors, chemical stability, or reactivity that enhances biological activity. Many are biosynthesized from sulfur-containing amino acids such as methionine and cysteine.

Etymology

From 'organic' (carbon-based chemistry) + 'sulfur' (the element S, from Latin sulphur) + 'compound' (substance formed by chemical union of elements).

Example

The stink bug Chlorochroa sayi releases a blend of trans-2-decenal and methyl thioalkanes as defensive secretions; the organic sulfur components contribute to the persistent, penetrating odor that deters vertebrate predators. In scorpions, venom peptides often contain disulfide bridges—covalent S–S bonds between cysteine residues—that stabilize the tertiary structure of neurotoxic peptides.

Synonyms

• organosulfur compounds
• organosulfur molecules

Related Terms

• allomone
• defensive secretion
• disulfide bond
• thiols
• semiochemistry
• venom biochemistry
• methionine
• cysteine

Usage Notes

Distinguished from inorganic sulfur compounds (e.g., sulfates, sulfites) by the presence of carbon–sulfur bonds. In entomological literature, 'organosulfur' is often preferred as a single word; 'organic sulfur' may appear in broader biochemical contexts. The term encompasses both small volatile molecules (e.g., dimethyl disulfide in carrion beetle pheromones) and macromolecular structures (e.g., sulfur-rich proteins in spider silk). Not all sulfur-containing biomolecules qualify: free sulfate ions and metal sulfides are excluded.