Question

Stearic acid (CH3(CH2)16COOH) is a common long-chain acid found in waste streams. Many microorganisms are capable of using stearic acid and derived metabolites as substrates. Determine the maximum ATP yield (mmol ATP/g stearic acid) that can be achieved from the complete oxidation of stearic acid to water and CO2 during aerobic microbial respiration in typical cellular environments. For your calculation, you may assume that after electron transport driven ATP synthesis, 3 ATP molecules are produced per NAD(P)H and 2 ATP per FADH2. You may also assume that GTP is equivalent to ATP

I need to know the steps involved in this problem.

Answer 1

For the oxidation of the stearic acid we will get 9 Acetyl coA 8 FADH₂ and 8 NADH this is because stearic acid is an even chain fatty acid and is consist of 18 carbons.

So, in this case the amount of ATP produced from the complete oxidation of Acetyl CoA is 10 so in this case 9 Acetyl CoA is present total ATp will be 9x10 = 90

Complete oxidation of 1 NADH gives us 3 ATP so the total ATP will be 8 x 3 = 24

Complete oxidation of one FADH₂ gives us 2 ATP so from FADH₂ total ATP will be 8 x 2 = 16 ATP

so the total ATP will be 90+16+24 = 130 this is the total ATP produced now in the step of activation of Fatty acids we lost 2 ATP there so the net gain of ATP will be 130-2 = 128. This is your answer. The ATP produced from the acetyl CoA is through the TCA cycle and ETS.