Biochem Q

[zhopv10]

So i came across a question in Uworld that said that increased organic acids (methylmalonic acid in this case) inhibit gluconeogenisis, and inhibit the urea cycle leading to hyperammonemia. Anyone know the mechanism of this?


Sent from my iPhone using SDN mobile app

---

Members don't see this ad.

 

[teehees]

QID?

 

[zhopv10]

1341 [733037]


Sent from my iPhone using SDN mobile app

 

[dorster]

I actually just had this same question come up on Uworld. I think its because since there is a deficiency in the enzyme methylmalonyl coA mutase or the cofactor vitamin B12 and you can't produce succinyl CoA from methylmalonyl CoA which means no succinylcoA and that means the TCA cycle can't go forward. Without the TCA cycle you won't generate enough Oxaloacetate which gets converted to aspartate to enter the urea cycle. basically a long explanation meaning without the first enzyme --> no succinyl coA --> no TCA--> no urea cycle = build up ammonia in the blood

I'm not the best at biochem but that was the only explanation I could come up with

 

[zhopv10]

^ah ok ya that makes sense, I got hung up on their explanation sounding like those would occur with any organic acidosis but ya probably more specific to this disease state in particular. I was totally missing the oxaloacetate urea cycle connection, nice!


Sent from my iPhone using SDN mobile app