Tyrosylprotein sulfotransferases and nucleic acids encoding the tyrosylprotein sulfotransferases are described. Dual isotopes of the enzyme and of the nucleic acids encoding said enzymes have been identified in human, mouse and C. elegans. The polypeptides and polynucleotides exhibit a wide range of homologies. The polynucleotides can be used to transform or transfect host cells for producing substantially pure forms of the enzyme, or for use in an expression system for post-translational tyrosine sulfation of proteins or peptides produced within the expression system. The enzymes can be used to sulfate peptides or proteins requiring sulfation.