Some observations on the interaction of dopamine-beta-hydroxylase and its natural inhibitors in the rat brain.
The difficulty of assaying dopamine beta-hydroxylase (DbetaH) (EC 1.14.17.1) has been circumvented by including N-ethylmaleimide (5 X 10(-2) M) in the incubation mixture along with a small amount of Cu2+ (20-60 muM). Such a procedure ensures that the maximum DbetaH activity is assessed in all extracts. As a result, the absolute levels of DbetaH in various regions of the rat brain have been established. The DbetaH values obtained are higher by 40% in the hypothalamus and 20% in the cerebral cortex, spinal cord, and caudate nucleus than those previously reported. The mechanism of the synergic effect seen when N-ethylmaleimide and Cu2+ are combined is not presently understood.
D000311:Adrenal Glands / Q000201:enzymology; D000818:Animals; D001921:Brain / Q000201:enzymology* / Q000502:physiology; D001933:Brain Stem / Q000201:enzymology; D002421:Caudate Nucleus / Q000201:enzymology; D002540:Cerebral Cortex / Q000201:enzymology; D003300:Copper / Q000494:pharmacology; D004299:Dopamine beta-Hydroxylase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005033:Ethylmaleimide / Q000494:pharmacology; D007031:Hypothalamus / Q000201:enzymology; D007700:Kinetics; D008297:Male; D008780:Methyltransferases / Q000037:antagonists & inhibitors; D009928:Organ Specificity; D051381:Rats; D013116:Spinal Cord / Q000201:enzymology
D003300:Copper; D004299:Dopamine beta-Hydroxylase; D008780:Methyltransferases; D005033:Ethylmaleimide