N-3-oxo-pentanoyl-L-Homoserine lactone is a chain-shortened derivative of the bacterial quorum sensing signaling molecule N-3-oxo-octanoyl-L-homoserine lactone .1It inhibits binding of the autoinducer N-3-oxo-hexanoyl homoserine lactone toE. colicontaining the transcription factor LuxR when used at a concentration of 230 nM.2It acts as an autoinducer to activate theV. fischeriluminescence system inE. coliwhen used at concentrations ranging from 20 to 200 nM.