ChEBI

A molecular messenger in which the molecule is specifically involved in transmitting information between cells. Such molecules are released from the cell sending the signal, cross over the gap between cells by diffusion, and interact with specific receptors in another cell, triggering a response in that cell by activating a series of enzyme controlled reactions which lead to changes inside the cell.

Any intermediate or product resulting from metabolism. The term 'metabolite' subsumes the classes commonly known as primary and secondary metabolites.

A signalling molecule produced and used by bacteria participating in quorum sensing, that is, in cell-cell communication to coordinate community-wide regulation of processes such as biofilm formation, virulence, and bioluminescence in populations of bacteria. Such communication can occur both within and between different species of bacteria.