Reaction product affinity regulates activation of human sulfotransferase 1A1 PAP sulfation

► An ordered kinetic mechanism is confirmed for human sulfotransferase 1A1. ► Addition of phenol activates the reaction by intercepting E-PAPS and converting it to E-PAP. ► Activation requires a non-sticky alcohol substrate. ► Analogs of the alcohol or sulfated alcohol reactants should be effective inhibitors.