Ascorbic acid suppresses the deconjugation of noradrenaline but not dopamine in plasma.
The characteristics of hydrolysis of sulfoconjugated noradrenaline (NA) and dopamine (DA) in plasma using sulfatase were investigated. Ascorbic acid has been used as an antioxidant during the hydrolysis of conjugated NA or DA. Hydrolysis of NA sulfates was considerably inhibited by adding ascorbic acid (0.5-10 mM), and slightly inhibited by adding dithiothreitol (1-10 mM). In contrast, the hydrolysis of DA sulfates was not affected after either ascorbic acid or DTT treatment. On the basis of these findings, the levels of NA sulfates previously reported are found to be markedly lower than the actual levels of NA sulfates in human plasma.
Okada
M
M
Department of Psychosomatic Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Mine
K
K
Fujiwara
M
M
D001205:Ascorbic Acid / Q000494:pharmacology*; D004229:Dithiothreitol / Q000494:pharmacology; D004298:Dopamine / Q000097:blood*; D006801:Humans; D006868:Hydrolysis / Q000187:drug effects; D009638:Norepinephrine / Q000097:blood*; D013429:Sulfatases / Q000097:blood; D013431:Sulfates / Q000097:blood
D013431:Sulfates; D013429:Sulfatases; D001205:Ascorbic Acid; D004229:Dithiothreitol; D004298:Dopamine; D009638:Norepinephrine