SULT4A1,also named as SULTX3,NST,ST4A1,hBR-STL and hBR-STL-1,belongs to the sulfotransferase 1 family. It may catalyze the sulfate conjugation of many drugs,xenobiotic compounds,hormones,and neurotransmitters. SULT4A1 displays activity towards L-triiodothyronine,thyroxine,estrone,p-nitrophenol,2-naphtylamine,and 2-naphtol. It may have a role in the sulfation of drugs and neurotransmitters in the CNS. SULT4A1 is a brain-specific sulfotransferase believed to be involved in the metabolism of neurotransmitters. It is a novel cytosolic sulfotransferase that is primarily expressed in the brain.