Absence of differences in platelet dihydroxyphenylalanine (dopa) oxidase polymorphism in health and Duchenne's muscular dystrophy.

Extracts of platelets were subjected to vertical starch gel electrophoresis followed by enzyme staining to further investigate earlier reports of a unique dihydroxyphenylalanine (DOPA) oxidase polymorphism among boys with Duchenne's muscular dystrophy (DMD) and their mothers. This was said to be distinct from those found in healthy controls. Platelets were separated from citrated venous blood by differential centrifugation and checked for purity by phase contrast microscopy. The isolated platelets were disrupted by freeze-thawing in Tris-HC1 buffer (0.02M, pH 8.2), and the resulting platelet extracts were electrophoresed for 15 hours at 130V at 4 degrees C. The starch gels were then sliced and stained with 0.2% DOPA and 0.1% MnCl2. Three electrophoretic patterns of DOPA oxidase activity were found in normal men and women: a single rapidly moving band; a single slowly moving band; and a broad band. These three patterns were also seen in boys with DMD, their mothers, and their fathers. Thus, a unique polymorphism was not found in boys with Duchenne's muscular dystrophy or their carrier mothers.