Enzyme measurements on single cells.

A simple and sensitive procedure has been developed for enzymatic assays in single cells and applied to the measurement of beta-glucuronidase in single parenchymal cells of liver. Cells deposited in microdroplets under oil were ruptured by freezing and thawing and allowed to react with a fluorogenic substrate. The fluorescence is developed by diffusing an organic base into the droplets and measured in a fluorescence microscope equipped with a photomultiplier.