Question: As we were looking through lab exercise and discussing it during class, I saw that we would be working with the LDH gene. I had heard of the LDH protein in my previous biochemistry classes, but as to what function it had in the body, I did not really know. My question would be what is LDH, what does it do, and what relevance does it have in the medical world?

Answer: LDH, or lactate dehydrogenase is an enzyme that catalyzes the conversion of pyruvate to lactate and vice versa by using NADH and NAD+ to donate and accept protons. Proton acceptance from NADH is usually performed by oxygen, turning oxygen into water. In the absence of oxygen, this role is filled by pyruvate. LDH is found in all the domains of life in almost all living cells. In humans, LDH is a protein that is not supposed to appear in the blood at high levels, and levels are often measured in the doctor’s office to detect and monitor health abnormalities. Since LDH is released into the blood when cells have been damaged or destroyed, high levels of LDH indicate that there has been tissue damage somewhere in the body. It is used to test for a broad range of illnesses, including “cancer, heart failure, hypothyroidism, anemia, pre-eclampsia, meningitis, encephalitis, acute pancreatitis, HIV, and lung or liver disease.”

LDH is often associated with contributing to muscular fatigue due to in its production of lactate during exercise., However, but experiments have shown that although LDH seems to be connected with muscle fatigue, it does not cause it. Interestingly, it actually helps prevent muscular acidosis and delays the fatigue that is caused by those unaccepted NADH protons by transferring them to pyruvate. This allows the pyruvate to lactate reaction to act as a kind of buffer, keeping the protons from accumulating and causing the muscular acidosis and fatigue.

  • Natalya R.

References:

  1. https://labtestsonline.org/understanding/analytes/ldh/tab/test/
  2. https://en.wikipedia.org/wiki/Lactate_dehydrogenase
  3. Stanford Cancer Center. “Cancer Diagnosis – Understanding Cancer”Understanding Cancer. Stanford Medicine.
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