Isolation and Characterization of Glucocerebrosidase from Human Placental Tissue

Human placental glucocerebrosidase was purified 4000-fold to apparent homogeneity. The most highly enriched preparation catalyzes the hydrolysis of 1 mmole of glucosylceramide per mg of protein per hour. Although the molecular size of the enzyme depends on the method of extraction, the purified protein is a tetramer composed of 4 catalytically active units whose mass is 60,000 daltons each. The enzyme shows an absolute specificity for β-d-glucopyranoside bonds and it is most active with the natural substrate glucocerebroside. It is less active with various synthetic β-glucoside substrates. The relationship of this enzyme to total tissue β-glucosidase activity is discussed.