Control and function of the transamination pathways of glutamine oxidation in tumour cells.

Abstract

Parallel investigations of the transamination pathways of glutamine oxidation in Ehrlich ascites carcinoma (EAC) and AS 30D hepatoma revealed that hepatoma cells, unlike EAC, produce very little aspartate. This cannot be explained by differences in the activity of glutamine-metabolizing enzymes. Also, the mitochondria from the hepatoma respired at a similar rate to EAC mitochondria with glutamine as sole substrate producing substantial amounts of aspartate. Unlike their isolated mitochondria, intact hepatoma cells showed a very low rate of glutamine oxidation. Compared with EAC, the rate of L-[U-14C]glutamine consumption by AS 30D hepatoma cells was much lower, with insignificant production of 14C-labelled aspartate and CO2. This suggested that the glutamine-transporting system in the hepatoma cell plasma membrane had a very low activity. Isolated hepatoma mitochondria produced 3 times more pyruvate from malate than did EAC mitochondria, indicating a higher activity of NAD(P)-dependent malic enzyme. We postulate that an active malic enzyme may suppress the synthesis of aspartate in hepatoma cells, but further evidence is needed to confirm this assumption.

Statistics

0100200300'96'98'00'02'04'06'08'10'12'14'16
Citations per Year

206 Citations

Semantic Scholar estimates that this publication has 206 citations based on the available data.

See our FAQ for additional information.

Cite this paper

@article{Kovaevi1991ControlAF, title={Control and function of the transamination pathways of glutamine oxidation in tumour cells.}, author={Zorica Kova{\vc}evi{\'c} and O Brkljac and K Bajin}, journal={The Biochemical journal}, year={1991}, volume={273(Pt 2)}, pages={271-5} }