Question

The amino acid alanine (Ala) can be broken down into pyruvate by the following reaction:

Ala + NAD + H2O ® pyruvate + NH4+ + NADH2
1A. Can E. coli survive with Ala as the sole carbon source in the presence of O2? (yes) (no)

(cannot predict)
1B. If so, how many ATP will be produced per molecule of Ala. Show your work.

1C. If Krebs cycle is blocked with an inhibitor, can E. coli survive with Ala as the sole carbon source in the presence of O2? (yes) (no) (cannot predict) If so, how many ATP per molecule of Ala? If not, why?

1D. If the electron transport chain (ETC) and oxidative phosphorylation are blocked, can E. coli survive with Ala as the sole carbon source in the presence of O2? (yes) (no) (cannot predict)

Answer 1

1A. Yes, it can survive with alanine.

1B. Coversion of alanine to pyruvate produces one NADH2. This gives three ATP.

Pyruvate to acetyl CoA will produce one NADH2. This gives three ATP.

TAC cycle produces 12 ATP.

Total ATP produced per alanine = 3+ 3+ 12 = 18.

1C. Yes, it can survive.

Coversion of alanine to pyruvate produces one NADH2. This gives three ATP.

Pyruvate to acetyl CoA will produce one NADH2. This gives three ATP.

Totally six ATPs will be produced without TCA cycle.

1D. No, it cannot survive without ETC and oxidative phosphorylation because all its NADH2 has to go to TCA for the production of ATP.