Table 1

The human sulfotransferase enzyme family

SULT1A1SULT1A2SULT1A3SULT1B1SULT1C11-aSULT1C21-a1-bSULT1E1SULT2A1SULT2B1aSULT2B1b
Simple phenolsSimple phenolsCatecholaminesSimple phenols N-Hydroxy-2-acetylaminofluorene?EstroneDHEADHEADHEA
CatecholsCatecholsCatecholsCatecholsEstradiolPregnenolone??
MinoxidilTyramineIodothyroninesEstriolCholesterol
Paracetamol5-Hydroxytryptamine17α-EthinylestradiolCortisol
HydroxyarylaminesSalbutamolEquileninBenzylic alcohols of PAHs
IodothyroninesIsoprenalineDiethylstilbestrolTestosterone
DobutamineThyroxineBile salts

A novel SULT gene has been identified through the chromosome 22 sequencing project that shares approximately 30% amino acid sequence identity with other human SULTs. Provisional name, SULT4A1, EMBL accession numbers: CAB09788, AF115311. The function is as yet unknown.

  • 1-a  The SULT1C enzymes are named here on the basis that SULT1C1 is the ortholog of the rat SULT1C1 enzyme—the first of this family to be discovered (Nagata et al., 1993). The enzyme labeled SULT1C2 here is coded by the first human SULT1C cDNA to be cloned, which the authors named SULT1C1 (Her et al., 1997). The following EMBL accession numbers relate to the nomenclature as stated here: SULT1C1, AF055584; SULT1C2, U66036.

  • 1-b  SULT1C2 appears to be essentially a “dead” enzyme, i.e., little or no activity toward any standard substrate. It has an amino acid change in a conserved residue in the active site of the enzyme (Tyr241Arg), which may explain this.