High β-glucosidase (GBA) activity not attributable to GBA1 and GBA2 in live normal and enzyme-deficient fibroblasts may emphasise the role of additional GBAs.

Beta-glucosidases (GBA) include GBA1, GBA2 and other β-glucosidases (non-GBA1-2). GBA1 is a lysosomal and GBA2 an extra-lysosomal enzyme. GBA1- and GBA2-deficient genetic conditions, with different phenotypes, are glucosylceramide (GC; the main GBA substrate) accumulating diseases. To study the activity profile of GBA, live fibroblasts were loaded with radioactive GC. The GC metabolism was measured in wild-type, GBA1-deficient (Gaucher disease) and GBA2-deficient (Gba2(-/- )mouse) cells. The differences found allowed the prediction of marked proportions of GBA1, GBA2, and particularly non-GBA1-2 (probably including GBA3, a cytosolic β-glucosidase) activity for wild-type cells. The high proportion of non-GBA1-2 suggests an important role of these enzymes.