Purification and characterization of tyrosylprotein sulfotransferase.

Tyrosylprotein sulfotransferase (TPST) is a Golgi membrane enzyme involved in the post‐translational modification of secretory and membrane proteins. Here we describe the 140,000‐fold purification of this enzyme from bovine adrenal medulla to apparent homogeneity and determine its substrate specificity. The key step in the purification was affinity chromatography on a substrate peptide to which the enzyme bound in the presence of nucleotide cosubstrate. TPST is a 54‐50 kd integral membrane glycoprotein. The presence of sialic acid strongly suggests that within the Golgi complex, TPST is localized in the trans‐most subcompartment. TPST was found to specifically sulfate tyrosine residues adjacent to acidic amino acids. These results define a major determinant for the specificity of protein sulfation in the trans Golgi.