Subcellular distribution of acid and neutral α-glucosidases in normal, acid maltose deficient, and myophosphorylase deficient human skeletal muscle

The subcellular distribution of acid (pH 4.0) and neutral (pH 6.5) α-glucosidases was investigated in biopsy specimens of human skeletal muscle obtained from six normal subjects, four adult cases of acid maltase deficiency, and a case of myophosphorylase deficiency. The highest relative specific activity of acid glucosidase, as well as of other acid hydrolases, was observed in the light mitochondrial fraction. Relatively high acid phosphatase activity was also found in the microsomal fraction. In all muscles the highest relative specific activity of neutral glucosidase was in the microsomal fraction. In acid glucosidase deficient muscle no neutral glucosidase could be detected in the light and heavy mitochondrial fractions but in normal and myophosphorylase deficient muscle neutral glucosidase activity was also detectable in these fractions. The final supernatant of all muscles contained neutral glucoamylase activity. The relevance of these data to the pathogenesis of the different forms of type II glycogenosis is considered.