Question

what and how do i detrimine the atp count for propnayl CoA in the tca cycle?

Answer 1

Propionyl CoA converts to methyl malonyl CoA in which one ATP is converted to ADP and Pi by the enzyme propionyl CoA carboxylase. The methyl malonyl CoA is then converted to succinyl CoA by methyl malonyl CoA isomerase. This succinyl CoA is metabolozed in TCA. So in one cycle TCA, normally we get 15 ATP (one NADH2 from pyruvate to acetyl CoA and 12 ATP from one acetyl CoA. so total 15 ATP). But in propionyl CoA , we will get one ATP less, so we will get 14 ATP in one conversion as one ATP is consumed in the conversion of propionyl CoA converts to methyl malonyl CoA. The succinyl CoA will takek part in TCA.

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