title: Uptake and stability of human and bovine acid alpha-glucosidase in cultured fibroblasts and skeletal muscle cells from glycogenosis type II patients.
abstract: Acid alpha-glucosidase (EC 3.2.1.20) was purified from human placenta and bovine testis by affinity chromatography using concanavalin A (conA) and Sephadex G 200. When added to the culture medium of human fibroblasts, the enzyme purified from bovine testis is taken up with a 200-fold higher efficiency than the enzyme from human placenta. Uptake of acid alpha-glucosidase from bovine testis is mediated by the mannose-6-phosphate receptor, whereas only a minor fraction of placental enzyme appears to be equipped with the mannose-6-phosphate recognition marker. Once internalized, both human and bovine acid alpha-glucosidase demonstrate a half-life of about 10 days in fibroblasts from control individuals and patients with different clinical forms of glycogenosis type II (Pompe's disease, acid alpha-glucosidase deficiency). Evidence is presented that the mannose-6-phosphate receptor is also present on the plasma membrane of the clonal myogenic skeletal muscle cell lines G8-1 and L6J1 (respectively from mouse and rat origin) and on cultured human skeletal muscle cells derived from a muscle biopsy. Addition of bovine testis acid alpha-glucosidase to skeletal muscle cell cultures from an adult patient with glycogenosis type II leads to complete correction of the enzyme deficiency.
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D004705:Endocytosis; D005260:Female; D005347:Fibroblasts; D005959:Glucosidases / Q000378:metabolism*; D006008:Glycogen Storage Disease / Q000201:enzymology*; D006009:Glycogen Storage Disease Type II / Q000201:enzymology*; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D009132:Muscles / Q000378:metabolism; D010920:Placenta / Q000201:enzymology; D017527:Receptor, IGF Type 2; D013737:Testis / Q000201:enzymology; D000520:alpha-Glucosidases / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D017527:Receptor, IGF Type 2; D005959:Glucosidases; D000520:alpha-Glucosidases