Surface-membrane defects in muscular dystrophy.

originally to do the work that developed methods for isolation of highly purified brush-border membranes from biopsy specimens as small as 10-15mg (Schmitz et al., 1973). In one early test, we found no difference in the banding pattern on gel electrophoresis between the brush-border membrane of a normal and a glucose-galactose-malabsorption biopsy. However, our further studies of reconstitution of glucose and amino acid transport (Fairclough et al., 1979) suggest that no difference would have been expected. We have progressed in purification to the point where a single protein band at 160000 daltons appears to be identified with active reconstituted preparations (Malathi et al., 1980). However, final proof that this band represents transporters still eludes us. Moreover, with regard to the identification of a loss of protein with a loss of glucose transport in glucose-galactose malabsorption, the probability that this band represents other transport systems in addition to glucose greatly lessens the chances at least at the present stage of purification.