Molecular Forms, Biosynthesis and Maturation of Glucocerebrosidase, a Membrane-Associated Lysosomal Enzyme Deficient in Gaucher Disease

Abstract

Glucocerebrosidase is a membrane-associated lysosomal enzyme. Its physiological funtion is to catalyse the hydrolysis of the β-glucosidic bonds in the glycosphingolipid glucocerebroside. There is a deficiency of the enzyme in Gaucher disease, which leads to excessive accumulation of glucocerebroside in cells of the reticuloendothelial system 1,2. Three phenotypes of Gaucher disease are recognized: type 1, the adult, nonneuronopathic form; type 2, the acute, neuronopathic form; and type 3, the subacute, neuronopathic form3. Attempts have been made to correlate the clinical phenotype with stored lipid, residual activity of the enzyme, molecular forms seen after isoelectric focussing, enzymological parameters of the residual enzyme activity, or extent of stimulation of delipidated splenic glucocerebrosidase by acidic phospholipids or a heat-stable “activator protein”, but no clear, consistent picture has emerged from the results of these studies (reviewed in refs. 4–7).