Prominent glutamine oxidation activity in mitochondria of avian transplantable hepatoma induced by MC-29 virus

✍ Scribed by Tetsuya Matsuno; Teikichi Satoh; Haruo Suzuki

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 644 KB
• Volume: 128
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1041280308

✦ Synopsis

Well coupled mitochondria were isolated from transplantable chicken hepatoma induced by MC-29 virus. The mitochondrial phosphate-dependent and phosphate-independent glutaminase activities were increased compared with those from normal chicken liver. Glutamate dehydrogenase was undetectable in the tumor mitochondria. Oxypolarographic tests showed the following: glutamine oxidation was prominent in the tumor mitochondria and was mediated through an NAD-linked reaction, while mitochondria from the liver showed a feeble glutamine oxidation; glutamine oxidation by tumor mitochondria was inhibited either by aminooxyacetate, inhibitor of transaminases, or prior incubation of mitochondria with DON (6-diazo-5-oxonorleucine), which inhibited mitochondrial glutaminases. Bromofuroate, inhibitor of glutamate dehydrogenase, had little or no effect; and glutamate oxidation was also inhibited by aminooxyacetate, while it was not affected by DON. These findings clearly show a high glutamate oxidation activity in the hepatoma and indicate that the product of glutamine hydrolysis, glutamate, is catabolized via transamination in the mitochondria to supply ATP.