Open AccessA membrane form of brain L-glutamate decarboxylase: identification, isolation, and its relation to insulin-dependent mellitus.
Author(s) -
Britto P. Nathan,
Jun Bao,
CheChang Hsu,
Patrícia Pereira Aguilar,
Runzhi Wu,
Mina Yarom,
ChihWen Kuo,
JangYen Wu
Publication year - 1994
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.91.1.242
Subject(s) - glutamate decarboxylase , immunoprecipitation , membrane protein , biochemistry , membrane , insulin , diabetes mellitus , biology , extracellular , chemistry , enzyme , endocrinology , gene
A membrane form of L-glutamate decarboxylase (GAD) was identified and purified 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 kDa and is a homodimer of 48 +/- 3-kDa subunits. Immunoprecipitation and immunoblotting tests revealed the presence of antibodies against this membrane GAD in sera from patients with insulin-dependent diabetes mellitus. Since this form of GAD appears to be an integral membrane protein and is presumed to have extracellular domains exposed, it seems reasonable to suggest that membrane GAD is more likely than soluble GAD to be involved in the pathogenesis of insulin-dependent diabetes and related autoimmune disorders such as stiff-man syndrome.