GABA (gamma-aminobutyrate). The antibody has been calibrated against a spectrum of antigens to assure hapten selectivity and proper affinity. No measurable glutaraldehyde-fixed tissue cross-reactivity (<1:1000) against L-alanine, 1-amino-4-guanidobutane (AGB), D/L-arganine, D/L-aspartate, L-citrulline, L-cysteine, D/L-glutamate, D/L-glutamine, glutathione, glycine, L-lysine, L-ornithine, L-serine, L-threonine, L-tryptophan, L-tyrosine.