SUBSTRATE-SPECIFICITY OF HUMAN MONOAMINE (M)-FORM PHENOL SULFOTRANSFERASE - PREPARATION AND ANALYSIS OF DOPA 3-O-SULFATE AND DOPA 4-O-SULFATE

Upon two-dimensional thin-layer separation, the sulfated L-3,4- dihydr oxyphenylalanine (L-DopaS) generated enzymatically was found to co-mig rate with only one of the two ninhydrin-stained spots corresponding to the two sulfated forms (3-O-sulfate and 4-O-sulfate) of synthetic L-D opaS, To clarify precisely the identity of the enzymatically generated L-DopaS, the two sulfated forms of synthetic L-DopaS were separated a nd purified using high performance liquid chromatography. Purified L-D opa 3-O-sulfate and L-Dopa 4-O-sulfate were identified by H-1-nuclear magnetic resonance (NMR) spectrometry and used as standards in the ana lysis of the L-DopaS generated during metabolic labeling of HepG2 huma n hepatoma cells or enzymatic assay using recombinant human monoamine (M)-form phenol sulfotransferase, The results obtained demonstrated un equivocally the generation of L-Dopa 3-O-sulfate, indicating the speci ficity of the M-form phenol sulfotransferase being for the meta-hydrox yl group of L-Dopa.