A simplified radioenzymatic assay for dopamine-beta-hydroxylase (DBH), utilizing partially purified phenyl-ethanol-N-methyl-transferase and 3(H)-S-adenosylmethionine, was developed and used to characterize DBH activity found in rat serum. The Km of DBH for ascorbic acid was 1.34 mM. The Km for tyramine was a complex function of the concentration of the allosteric activator, fumarate, and the relative concentration of cupric ion compared to inhibitor concentration. The kinetics of the effect of cupric ion on DBH inhibitor were investigated extensively.
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Pharmacology, Toxicology and Pharmaceutics(all)