Firefly bioluminescent assay of ATP in the presence of ATP extractant by using liposomes.

Liposomes containing phosphatidylcholine (PC) and cholesterol (Chol) were applied to the enhancer for firefly bioluminescence (BL) assay for ATP in the presence of cationic surfactants using as an extractant for the release of ATP from living cells. Benzalkonium chloride (BAC) was used as an ATP extractant. However, BAC seriously inhibited the activity of luciferase, thus resulting in the remarkable decrease in the sensitivity of the BL assay for ATP.