Skip to main content
. 2014 Feb 13;9(2):e88667. doi: 10.1371/journal.pone.0088667

Figure 3. Schematic of the fluorescence-coupled GABA assay.

Figure 3

The GABase preparation, a combination of ABAT and ALDH5A1 enzymes from P. fluorescens converts GABA to succinate through the conversion of alpha-ketoglutarate to glutamate and NADP to NADPH. Although NAD or NADP can potentially be used as substrates by ALDH5A1, NADP is conventionally used as a cofactor for this preparation. Succinic semialdehyde (SSAL), an intermediate of GABA metabolism is also metabolized by the GABase preparation. Diaphorase oxidizes the NADPH and reduces resazurin to fluorescent resorufin. Application of 2-aminoethyl hydrogen sulfate (2-AEHS), an inhibitor of ABAT can be used to determine the contribution of SSAL to the total signal generated from GABA and SSAL in cell lysates.