4-PENTAFLUOROETHYLUMBELLIFERYL-BETA-D-GLUCOSIDE AS A NEW FLUOROGENIC SUBSTRATE FOR ACID BETA-D-GLUCOSIDASE

4-Pentafluoroethylumbelliferyl-beta-D-glucoside is proposed as an effi cient substrate for human leukocyte acid beta-glucosidase. Its synthes is is described. This substrate was compared directly with 4-trifluoro methylumbelliferyl-beta-glucoside synthesized by us earlier and with 4 -methylumbelliferyl-beta-D-glucoside which is commonly used for acid b eta-glucosidase activity assay. The specific activity of acid beta-glu cosidase with 4-pentafluoroethylumbelliferyl-beta-D-glucoside was 3-an d 8-fold higher than it was with the substrates mentioned above. The k inetic parameters K-M and V-max for human leukocyte acid beta-glucosid ase with the three substrates was determined. One possible application of the newly synthesized substrate is its use in the diagnosis of aci d beta-glucosidase hereditary deficiency (Gaucher's disease).