Tyramine-O-sulfate, in addition to tyrosine-O-sulfate, is produced and secreted by HepG2 human hepatoma cells, but not by 3Y1 rat embryo fibroblasts.
The spent media of HepG2 human hepatoma cells and 3Y1 rat embryo fibroblasts labeled with [35S]sulfate, upon ultrafiltration, were analyzed by a two-dimensional thin-layer separation procedure. Autoradiographs of the cellulose thin-layer plate revealed the presence of tyramine-O-[35S]sulfate in addition to tyrosine-O-[35S]sulfate in spent medium from human hepatoma cells. In contrast, only tyrosine-O-[35S]sulfate was observed in spent medium of 3Y1 rat fibroblasts. Using adenosine, 3'-phosphate, 5'-phospho[35S]sulfate as the sulfate donor, sulfotransferase(s) present in HepG2 cell homogenate catalyzed the sulfation of tyramine to tyramine-O-[35S]sulfate, but not the sulfation of tyrosine to tyrosine-O-[35S]sulfate. Endogenous aromatic amino acid decarboxylase present in HepG2 homogenate was shown to catalyze the decarboxylation of [3H]tyrosine to form [3H]tyramine while attempts to use it for the decarboxylation of tyrosine-O-sulfate to form tyramine-O-sulfate were unsuccessful. These results suggest that tyramine-O-sulfate may be derived from the de novo sulfation of tyramine, instead of the decarboxylation of tyrosine-O-sulfate.
Liu
M C
MC
Department of Chemistry, University of Oklahoma, Norman 73019.
Yu
S
S
Suiko
M
M
D000818:Animals; D006528:Carcinoma, Hepatocellular; D002855:Chromatography, Thin Layer; D003653:Decarboxylation; D005347:Fibroblasts; D006801:Humans; D008113:Liver Neoplasms; D051381:Rats; D015238:Sulfotransferases / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014439:Tyramine / Q000031:analogs & derivatives* / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism
C005662:tyrosine O-sulfate; D014443:Tyrosine; D015238:Sulfotransferases; C027957:tyramine O-sulfate; D014439:Tyramine