Does PAPS generation determine the overall sulfate conjugation in human platelets?
The formation of 3'-phospho-adenosine-5'phosphosulfate (PAPS) depends on essentially two enzymic reactions catalysed by ATP-sulfurylase and APS-kinase (adenosine 5'-phosphosulfate-kinase). In this paper, PAPS generation by human platelets was determined by the transfer of 35sulfate from PAP35S formed in vitro to N-acetyldopamine (NADA), using the phenolsulfotransferase extracted from rat liver. A pre-requisite of this quantitative procedure was the prior inhibition of the sulfate-activating system in the latter enzyme preparation. This was accomplished by the addition of 10 mM EDTA and 14 mM pyrophosphate. The PAPS-generating system of human platelets exhibited two pH peaks with higher activity at pH 8 than pH 6. Optimal concentrations of ATP and Mg++ at 7 mM were required for the two reactions. PAPS generation so measured showed a highly significant correlation with the overall sulfate conjugation of NADA: a correlation coefficient of 0.96 was established from data obtained from 60 platelet preparations of normal subjects.
D000227:Adenine Nucleotides / Q000097:blood*; D000328:Adult; D000818:Animals; D015239:Arylsulfotransferase; D001792:Blood Platelets / Q000378:metabolism*; D004298:Dopamine / Q000031:analogs & derivatives / Q000097:blood; D004492:Edetic Acid / Q000494:pharmacology; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008099:Liver / Q000201:enzymology; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D010724:Phosphoadenosine Phosphosulfate / Q000097:blood*; D051381:Rats; D013431:Sulfates / Q000097:blood*; D013462:Sulfur Radioisotopes; D013466:Sulfurtransferases / Q000378:metabolism
D000227:Adenine Nucleotides; D013431:Sulfates; D013462:Sulfur Radioisotopes; C006374:N-acetyldopamine; D010724:Phosphoadenosine Phosphosulfate; D004492:Edetic Acid; D013466:Sulfurtransferases; D015239:Arylsulfotransferase; D008274:Magnesium; D004298:Dopamine