Inhibition of rat brain galactocerebroside sulfotransferase by triazine aromatic dyes: interaction with the 3'-phosphoadenosine 5'-phosphosulfate binding site.

The mechanism of inhibition of rat brain cerebroside sulfotransferase (EC 2.8.2.11) by a series of triazine aromatic dyes was examined. These dyes are putative site-specific probes of the "dinucleotide fold". All of the dyes examined were competitive inhibitors of cerebroside sulfotransferase with respect to 3'-phosphoadenosine 5'-phosphosulfate (PAPS) binding. In addition, the binding of the dye, Congo Red, to the sulfotransferase was associated with a red shift in its absorption spectrum. Based on these results, it is suggested that rat brain cerebroside sulfotransferase contains a "dinucleotide fold" as a structural feature of the protein.