Lipophilic fluorescent glycosidase substrates

Abstract

The claimed invention relates to a substrate for evaluating glycosidic enzymes comprising a fluorescein derivative of the general formula: ##STR1## wherein GlyX is a carbohydrate bonded to fluorescein by a glycosidic linkage; Y, which may be the same as GlyX or different, is an alkyl ether, an ester, or a glycosidically linked carbohydrate; R is a lipophilic residue containing from 1 to 21 carbon atoms; and L links the R residue to fluorescein. A preferred embodiment of the invention is a non-fluorescent substrate specifically hydrolyzable by a glycosidase inside a cell to yield, after greater than about 2 minutes, a fluorescent detection product excitable at between about 460 nm and 550 nm and with fluorescence observable at an emission wavelength longer than the excitation wavelength, which fluorescent detection product is retained inside a viable cell more than about 2 hours at greater than about 15.degree. C. and which is non-toxic to the cell. A further embodiment of the invention is a method for evaluating a glycosidic enzyme in living plant or animal cells whether the enzyme is present endogenously; present as a result of manipulation of the cell's genome, or added to the cell exogenously, such as by covalently binding the enzyme to a protein to form an enzyme-protein complex that enters the cell.

Dependencies are inferred from the claim text.