Malate Shuttle and TCA Cycle

[wolfie77]

---

Members do not see this ad.

I think this isn't completely MCAT relevant but I didn't know where else to ask this question.

Why do both the malate shuttle (which pumps oxaloacetate out of the matrix of the mitochondria and into the cytoplasm) exist along with the TCA cycle (also in the matrix of the mitochondria)?

Essentially, why is oxaloacetate getting chugged out of the mitochondria when it is needed there to keep the TCA cycle going?

Any help/thoughts are greatly appreciated.

 

[house2272000]

As you might know certain intermediates of the TCA cycle can be used for gluconeogenesis, making DNA bases, and even certain amino acids. When you are fasting your body uses malate to make glucose. Glucose is made in the cytoplasm when fasting, so malate is shuttled out of the mitochondria. I you want a chart of gluconeogenesis let me know.

 

[wolfie77]

As you might know certain intermediates of the TCA cycle can be used for gluconeogenesis, making DNA bases, and even certain amino acids. When you are fasting your body uses malate to make glucose. Glucose is made in the cytoplasm when fasting, so malate is shuttled out of the mitochondria. I you want a chart of gluconeogenesis let me know.

Thanks a lot for your response. This makes more sense. I hadn't connected the dots back to gluconeogenesis in the cytoplasm. I would actually love a chart if it's not too much trouble.

 

[house2272000]

Below is the copy of gluconeogensis