Comparative study of biochemical parameters and kinetic properties of dopamine-beta-hydroxylase activity from cat and rat adrenals.
The specific adrenal dopamine-beta-hydroxylase activity measured in cat and rat was: (1) two times higher in cat than in rat; (2) significantly enhanced by ascorbate (up to 5 mM) that acts as a major activator; (3) differently affected by exogenous copper added to the incubation medium, leading to a decrease with large concentrations; and (4) similar, according to the kinetic parameters, thereby demonstrating a greater affinity for ascorbate than for tyramine.
Fortin
D
D
INRS-Santé, Université du Québec, Pointe-Claire, Canada.
Coulon
J F
JF
Roberge
A G
AG
D000311:Adrenal Glands / Q000201:enzymology*; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D002415:Cats / Q000378:metabolism*; D003300:Copper / Q000494:pharmacology; D004299:Dopamine beta-Hydroxylase / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley / Q000378:metabolism*; D013045:Species Specificity; D014439:Tyramine / Q000494:pharmacology
D003300:Copper; D004299:Dopamine beta-Hydroxylase; D001205:Ascorbic Acid; D014439:Tyramine