Step I FA 13 (Pg. 102 gluconeogenesis)

[drake19]

Hey eveyrone, Pg. 102, under the fact "Gluconeogenesis irreversible enzymes" and then the subtitle glucose-6-phosphtase...

does anyone understand which even-chain FA cannot produce new glucose but odd chain FA can?

The explanation that FA gives is that even-chained FA can only yield acetyl-CoA. The explanation I have gotten is that acetyl-CoA is only 2 carbons and can't enter TCA cycle...I'm not really sure what that means

Also succinyl-CoA can be created from odd-chain FA and then converted into pyruvate for gluconeogenesis is that correct?

 

[CassieBagley]

Hey eveyrone, Pg. 102, under the fact "Gluconeogenesis irreversible enzymes" and then the subtitle glucose-6-phosphtase...

does anyone understand which even-chain FA cannot produce new glucose but odd chain FA can?

The explanation that FA gives is that even-chained FA can only yield acetyl-CoA. The explanation I have gotten is that acetyl-CoA is only 2 carbons and can't enter TCA cycle...I'm not really sure what that means

Also succinyl-CoA can be created from odd-chain FA and then converted into pyruvate for gluconeogenesis is that correct?

to the best of my knowledge:
Even chain FAs get broken own by ACC into only Acetyl-CoA , whereas odd chain FAs get broken down by ACC into Acetyl-CoA & Propionyl-CoA. Proprioyl-CoA then enters the TCA cycle after being converted to succinyl-CoA. From there, it can go on to form OAA, which is a direct gluconeogenic precursor. The Acetyl-CoA generated form both even chain FAs and odd chain FAs, however, is not gluconeogenic because it would need OAA to enter the TCA in the form of citrate. Propionyl-CoA just jumps right into the TCA whereas Aceyl-CoA would be waiting for another entire carbon skeleton (OAA) to help it out.

 

[drake19]

ok thanks