Differential Distribution of Phenol and Catechol Sulphotransferases in Human Liver and Intestinal Mucosa

Abstract

Phenol and catechol sulphotransferases were studied with β-nitrophenol and dopamine as substrates in the mucosa of the ileum and colon obtained from 6 subjects and also in the liver from 6 subjects. The ileum and colon were from the same donor. The kinetics of phenol and catechol sulphotransferases were studied in each tissue specimen. The maximum velocity of reaction (V_max) for phenol sulphotransferase (in pmol × min^–1 × mg^–1; mean ± SD) was 165 ± 28 (ileum), 79 ± 42 (colon) and 1,361 ± 370 (liver), whereas V_maxfor catechol sulphotransferase was 489 ± 75 (ileum), 198 ± 93 (colon) and 39 ± 23 (liver). Phenol sulphotransferase is the predominant pathway in the liver, whereas catechol sulphotransferase is the predominant pathway in the intestine. The ileum catalysed the sulphation of p-nitrophenol and dopamine at a higher rate than the colon. The Michaelis-Menten constant (K_m) for phenol sulphotransferase (in μmol/l; mean ± SD) was 0.96 ± 0.11 (ileum), 1.00 ± 0.19 (colon) and 0.84 ± 0.07 (liver), whereas K_m for catechol sulphotransferase was 17.8 ± 2.8 (ileum), 18.2 ± 3.4 (colon) and 21.4 ± 1.2 (liver). K_m values of hepatic phenol or catechol sulphotransferases are not different from those of intestinal enzymes. Previous work has shown that 2-naphthol sulphotransferase obeys non-Michaelis-Menten kinetics in the human intestinal mucosa [Pharmacology, 1988;43:411]. Here, we show that 2-naphthol is sulphated by at least two enzymes in human intestine.

Interindividual variability in the N‐sulphation of desipramine in human liver and platelets.

“…The paucity of data on human liver N-and O-sulphotransferases makes it difficult to assess whether these enzymes are under common or different control. The limited evidence available, based on interindividual variability of 2-naphthol (Pacifici et al, 1988) and ethinyloestradiol (Temellini et al, 1991) sulphation, the symmetric frequency distribution histogram of O-sulphotransferase (Temellini et al, 1991) and the higher rate of O-sulphotransferase in ileum than colon (Cappiello et al, 1990b;Pacifici et al, 1989) suggests that O-sulphotransferase and N-ST activity are under independent control. The rates of p-nitrophenol-and dopamine-sulphation measured in 100 human livers do not correlate with the rate of DMI N-ST (unpublished data).…”

Dopamine Sulphotransferase Is Better Developed than p-Nitrophenol Sulphotransferase in the Human Fetus

“…In the text, we have used the terms TS and TL to refer to the two forms of sulpho transferase. In a previous study, we observed that TS and TL have independent distribu tion patterns in human liver and intestine, the TS being prevalently localized in the liv er, whereas TL is the prevalent one in the gut [6], This prompted us to investigate whether such a differential distribution pattern is consistent in human fetal tissues. We have also observed that the sulphation of 1-naphthol occurs in the human fetal liver at a rate one third of that in the adult liver, thus sug gesting that sulphotransferase is well devel oped in the human fetus [7], Up to now, it was unknown whether TS and TL obey inde pendent development patterns.…”

Synthetic calibrators for the analysis of total metanephrines in urine: Revisiting the conditions of hydrolysis

“…Sulfotransferase 1A3 (SULT1A3) catalyzes the transfer of a sulfonyl group from the sulfate donor, 3′-phosphoadenosine-5′-phosphosulfate (PAPS), to the free remaining hydroxy in position 4 of the phenyl ring of metanephrines [2]. SULT1A3 is predominantly expressed in the intestinal mucosa [3].…”