Electrophoretic separation of neutral and acid beta-glucosidase isozymes in human tissues.

An electrophoretic system using cellulose acetate has been developed for the resolution of beta-glucosidase isozymes (beta-D-glucoside glucohydrolase, EC 3.2.1.21 and D-glucosyl-N-acylsphingosine glucohydrolase, EC 3.2.1.45) in human tissue homogenates. Electrophoresis of homogenates from normal and Type 1 Gaucher disease tissues revealed two fluorescent bands of beta-glucosidase activity which corresponded to the acid and neutral isozymes separated by concanavalin A-Sepharose chromatography. The acid isozyme has only beta-glucosidase activity, whereas the neutral isozyme also exhibited alpha-L-arabinosidase (alpha-L-arabinofuranoside arabinofuranohydrolase, EC 3.2.1.55), beta-D-galactosidase (beta-D-galactoside galactohydrolase, EC 3.2.1.23) and beta-D-xylosidase (1,4-beta-D-xylan xylohydrolase, EC 3.2.1.37) activities, using the appropriate 4-methylumbelliferyl glycoside. In homogenates of cultured skin fibroblasts, only the acid isozyme was observed which co-electrophoresed with the acidic activity in other tissue homogenates. The acidic activity in tissue and fibroblast homogenates from Type 1 Gaucher disease appeared to co-electrophorese with the acid isozyme in normal tissues, but had markedly reduced activity.