Dopamine 4-sulfate is a major circulating plasma metabolite and urinary metabolite of dopamine formed by cytosolic sulfotransferase 1A3 (SULT1A3) from both exogenous and endogenous dopamine. Dopamine 4-sulfate has been shown to bind to the GABA receptor, but not to D1 or D2 dopamine receptors. Dopamine 4-sulfate is 10 times more abundant than isomeric dopamine 3-sulfate and is considered a potential biomarker for banana and other fruits consumption.