Apparent identity of cerebral tyrosylsulfotransferase activities using either a cholecystokinin derivative or an acidic amino acid polymer as substrate

Abstract
The tyrosylsulfotransferase activities of rat cerebral fractions transferring [35S]sultate groups from 3'‐phosphoadenosine 5'‐[35S]phosphosulfate to either Boc‐cholecystokinin‐8 (in non‐sulfated form) or the acidic amino acid polymer (Glu, Ala, Tyr) n (6:3:1) were compared. They appear similar regarding subcellular distribution (both being enriched in the microsomal fraction) and inhibition by an excess of the acidic amino acid polymer, NaCl or 2,6‐dichloro 4‐nitrophenol. These results obtained with artificial substrates suggest that identical (or closely similar) tyrosylsulfotransferases are responsible for sulfation of tyrosine residues of several secretory proteins from various tissues.