Stabilising normal and mis-sense variant α-glucosidase

α-Glucosidase (EC 3.2.1.3) is a lysosomal enzyme that hydrolyses α-1,4- and α-1,6-linkages of glycogen to produce free glucose. A deficiency in α-glucosidase activity results in glycogen storage disorder type II (GSD II), also called Pompe disease. Here, d-glucose was shown to be a competitive inhibitor of α-glucosidase and when added to culture medium at 6.0 g/L increased the production of this protein by CHO-K1 expression cells and stabilised the enzyme activity. d-Glucose also prevented α-glucosidase aggregation/precipitation and increased protein yield in a modified purification scheme. In fibroblast cells, from adult-onset GSD II patients, d-glucose increased the residual level of α-glucosidase activity, suggesting that a structural analogue of d-glucose may be used for enzyme enhancement therapy.