Antibodies against the bovine brain glutamate binding protein

Antibodies against the purified bovine brain glutamate binding protein (GBP) were raised in rabbits. Both nonderivatized and dinitrobenzene-derivatized GBP produced strong immunological responses in rabbits. Using the enzyme-linked immunosorbent assay (ELISA), we have quantified the antibody production and determined the specificity of the antibodies. Bovine brain GBP and the analogous protein from rat brain interacted most strongly with the antibodies. A bacterial glutamate-aspartate binding protein, as well as the enzymes glutamate dehydrogenase (EC 1.4.1.3), glutamine synthetase (EC 6.3.1.2), and gamma-glutamyl transpeptidase (EC 2.3.2.2), showed little or no cross-reactivity with the anti-GBP antibodies. A crude bacterial glutamate decarboxylase (EC 4.1.1.15) preparation gave a small to moderate cross-reaction with the anti-GBP antibodies. The sensitivity of the ELISA assay and the specificity of the antibodies were such that GBP levels as low as 3-10 ng could be detected.