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Glutamine synthetase and glutaminase activities in various hepatoma cells.

Authors
  • Matsuno, T
  • Hirai, H
Type
Published Article
Journal
Biochemistry international
Publication Date
Aug 01, 1989
Volume
19
Issue
2
Pages
219–225
Identifiers
PMID: 2573354
Source
Medline
License
Unknown

Abstract

Glutamine synthetase and glutaminase activities in a series of hepatoma cells of human and rat origins were determined for comparison with normal liver tissues. Marked decrease in glutamine synthetase activity was observed in the tumor cells. Phosphate-dependent and phosphate-independent glutaminase activities were increased compared with those from normal liver tissues. Well coupled mitochondria were isolated from HuH 13 line of human hepatoma cells and human liver. Oxypolarographic tests showed that glutamine oxidation was prominent in the tumor mitochondria, while mitochondria from the liver showed a feeble glutamine oxidation. Glutamine oxidation was inhibited by prior incubation of the mitochondria with DON (6-diazo-5-oxo-L-norleucine), which inhibited mitochondrial glutaminase. These results indicate that the product of glutamine hydrolysis, glutamate, is catabolized in the tumor mitochondria to supply ATP.

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