A revised fluorometric assay for Gaucher's disease using conduritol-beta-epoxide with liver as the source of Beta-glucosidase.

To date, enzymatic diagnosis of Gaucher's disease via a fluorometric assay procedure which utilizes 4-methylumbelliferyl-beta-D-glucopyranoside as a substrate has not been possible when liver serves as the source of enzyme since currently employed fluorometric procedures cannot adequately differentiate between a broad-specificity beta-glucosidase and lysosomal glucocerebrosidase activities in crude extracts of liver. Incorporation of conduritol-beta-epoxide into the incubation medium for the fluorometric assay allows one to selectively measure the glucocerebrosidase activity present in a given liver extract. In five cases of Gaucher's disease this revised fluorometric procedure proved as effective as the assy procedure which utilizes authentic, radiolabeled glucocerebroside as the substrate in demonstrating a deficiency of glucocerebrosidase activity in liver.