Glutamic Acid Decarboxylase, Brain, Membrane Form

Nathan et al. (1994) identified a membrane form of L-glutamate decarboxylase and purified it to apparent homogeneity from hog brain. The purified GAD was established as an integral membrane protein by phase-partitioning assay, charge-shift electrophoresis, and chromatography on a hydrophobic interaction column. This membrane GAD has a native molecular mass of 96 +/- 5 kD and is a homodimer of 48 +/- 3 kD subunits. Immunoprecipitation and immunoblotting demonstrated antibodies against this membrane GAD in sera from patients with insulin-dependent diabetes mellitus. Nathan et al. (1994) suggested that this form of GAD is more likely to be involved in the pathogenesis of insulin-dependent diabetes and related autoimmune disorders such as stiff man syndrome (184850) than is soluble GAD.