Bioluminescence inhibition of bacterial luciferase by aliphatic alcohol, amine and carboxylic acid: Inhibition potency and mechanism

The inhibitory effects of hydrophobic molecules on the bacterial luciferase, BL, luminescence reaction were analyzed using an electrochemically-controlled BL luminescence system. The inhibition potency of alkyl amines, C_nNH₂, and fatty acids, C_mCOOH (m = n - 1), on the BL reaction increased with an increase in the alkyl chain-length of these aliphatic compounds. C_mCOOH showed lower inhibition potency than C_nNH₂ and alkyl alcohols, C_nOH, data for which have been previously reported. To make clear the inhibition mechanisms of the aliphatic compounds on the BL reaction, the initial rate of the BL reaction was measured and analyzed using the Dixon plot and Cornish-Bowden plot. The C₁₂OH inhibited the BL reaction in competition with the substrate C₁₁CHO, while C₁₂NH2 and C₁₁COOH inhibited in an uncompetitive manner with the C₁₁CHO. These results suggest that the alkyl chain-length and the terminal unit of the aliphatic compound determine the inhibition potency and the inhibition mechanism, respectively.