Question: in the figure from the article by thompson and deberardinis...
In the Figure from
the article by Thompson and DeBerardinis (shown below), it is
proposed to feed stable isotopically labeled
(Bis-1,6-13C) glucose and then to determine the amount
of L-lactate and Actyl-CoA with 13C. The amount of
13C metabolites can be determined on the basis of their
lighter weight using mass spec and related to normal or cancer
i) Trace the isotopically labeled carbon by pathway (only describe starting material and product, not every intermediate is required.) to the two metabolites analyzed (lactate, acetyl CoA).
ii) Explain why those 2-carbons have to be labeled.
iii) If more labeled glucose goes to L-lactate than to acetyl CoA, identify the pathways that are activated and why more L-lacte than acetyl CoA is observed.
iv) What would an increased ratio of labeled L-lactate to acetyl CoA imply for: glucose consumption and local tissue pH?