Assay of β-glucosidase 2 (GBA2) activity using lithocholic acid β-3-O-glucoside substrate for cultured fibroblasts and glucosylceramide for brain tissue

Beta (β)-glucosidase 2 (GBA2) is deficient in a form of human spastic paraplegia due to defects in ( ). GBA2 was proposed as a modifier of Gaucher disease, a lysosomal storage disease resulting from deficient β-glucosidase 1; GBA1. Current GBA2 activity assays using artificial substrates incompletely model the activity encountered . We studied GBA2 activity, using lithocholic acid β-glucoside or glucosylceramide as natural β-glucosidase substrates in murine tissues or cultured patient fibroblasts with the pathologic genotypes: ; ; ; and found expected and unexpected deviations from normal controls.