Glucocerebrosidase processing in normal fibroblasts and in fibroblasts from patients with type I, type II, and type III Gaucher disease

Abstract

Fibroblasts from normal subjects and patients with the three types of Gaucher disease were labeled with [3H]leucine. Glucocerebrosidase antigen was immunoprecipitated using affinity-purified Sepharose-bound antibody. Normal cells initially formed a 60-kDa polypeptide antigen that was gradually replaced by a broad band of antigen averaging 63 kDa. This position corresponds with that of mature fibroblast and placental enzyme. Processing of glucocerebrosidase in six unrelated patients with type I Gaucher disease and one patient with type III Gaucher disease was exactly the same as normal. In contrast, three patients with the severe infantile (type II) form of the disease manifested a very unstable enzyme; the 60-kDa band appeared transiently and the mature 63-kDa band was never seen. These results indicate that type II Gaucher disease may well be distinguishable from type I disease by virtue of the very unstable enzyme precursor. Contrary to some earlier reports, processing of glucocerebrosidase in type I disease appears to be entirely normal.