Cysteine metabolism in periportal and perivenous hepatocytes: Perivenous cells have greater capacity for glutathione production and taurine synthesis but not for cysteine catabolism |
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Authors: | D L Bella L L Hirschberger Y H Kwon M H Stipanuk |
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Institution: | (1) Division of Nutritional Sciences, Cornell University, Ithaca, New York, U.S.A., US |
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Abstract: | Summary. Hepatocyte preparations highly enriched in cells from either the periportal or the perivenous zone of the liver acinus were
prepared using a digitonin/collagenase perfusion method. Five enzymes of cysteine metabolism were assayed in both periportal
and perivenous preparations. The ratios of periportal to perivenous activity were 0.76, 0.60, 0.81, 1.62, and 1.01 for cysteine
dioxygenase, cysteinesulfinate decarboxylase, γ-glutamylcysteine synthetase, cystathionase, and asparate (cysteinesulfinate) aminotransferase, respectively. Only cysteinesulfinate
decarboxylase activity was significantly different between periportal and perivenous cells. In incubations with 2 mmol/L 35S]cysteine, total cysteine catabolism (35S]taurine plus 35S]sulfate) between periportal and perivenous cells was not different, which is consistent with the observation of similar
cysteine dioxygenase activity across the hepatic acinus. Consistent with the lower cysteinesulfinate decarboxylase activity
in periportal cells, 16% of the total catabolism of 35S]cysteine in periportal cells resulted in taurine synthesis compared to 28% in perivenous cells. A lower rate of 35S]glutathione synthesis was observed in periportal cells compared to perivenous cells, but γ-glutamylcysteine synthetase activity was not significantly different between perivenous and periportal cells. Cysteinesulfnate
decarboxylase can be added to the list of enzymes whose activities are markedly enriched in perivenous cells.
Received January 15, 2002 Accepted February 4, 2002 Published online September 4, 2002
Acknowledgements This work was supported by the National Research Initiative Competitive Grants Program/United States Department of Agriculture
Competitive Research Grant 02-37200-7583.
Authors' address: Dr. Martha H. Stipanuk, Division of Nutritional Sciences, 227 Savage Hall, Cornell University, Ithaca, NY 14853-6301, U.S.A.,
E-mail: mhs6@cornell.edu |
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Keywords: | : Cystathionase Cysteine dioxygenase Cysteinesulfinate decarboxylase γ -Glutamylcysteine synthetase Periportal hepatocytes Perivenous hepatocytes |
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