Question

Calculate the ATP yield from oxidation of arachidic acid,stearic acid, linoleic acid, and oleic acid. Taking into account the energy needed to activate the fatty acid and transport it into mitochondria.

Answer 1

Complete oxidation of fatty acids produces CO2 and water. It's a two step process. Every carbon is converted to acetyl coenzyme- A. In the beta oxidation process, n/2 - 1 NADH, n/2 - 1 FADH2 and n/2 Acetyl CoA are produced. NADH produces 2.5, FADH2 gives 1.5 and Acetyl CoA gives 10 ATP in the case of saturated fatty acids with n carbon atoms Consider the saturated ones in the problem. arachidic acid 9 NADH + 9 FADH2 + 10 Acetyl COA → 9 (2.5)+ 9 (1.5) + 10 (10) ► 136 ATP Net ATP gain = 136-21 for ATP activation) = 134 stearic acid 8 NADH + 8 FADH2 +9 Acetyl COA → 8(2.5)+ 8(1.5) + 9 (10) ► 122 ATP Net ATP gain = 122–2( for ATP activation) = 120 linoleic acid It has two double bonds So number of FADH2 = (n/2) - 1-number of double bonds = (18/2)-1-2 = 6 8 NADH + 6 FADH2 + 9 Acetyl COA → 8(2.5)+ 6(1.5) + 9 (10) ► 119 ATP Net ATP gain = 119-21 for ATP activation) = 117 oleic acid It has one double bond So number of FADH2 = (n/2) - 1-number of double bonds = (18/2)-1-1=7 8 NADH + 7 FADH2 + 9 Acetyl COA → 8(2.5)+7(1.5) + 9 (10) ► 120.5 ATP Net ATP gain = 120.5-2 for ATP activation) = 118.5