The alanine transaminase test is one of the liver function tests that is used to confirm liver malfunction. Alanine transaminase is a liver enzyme that is part of the energy production cycle called the Kreb’s cycle in which energy is converted from stored glycogen into Adenosine Triphosphate, which the energy creation molecule in mitochondria. Alanine transaminase comes into play in the Alanine cycle in biochemistry. When there are elevated levels of this enzyme beyond the ranges of 1-56 units per liter, it is an indication of liver malfunction and a marker for hepatitis. This is because the liver during inflammation and damage ends up leaking out some crucial enzymes in the blood; however this is not the absolute test for hepatitis because alanine transaminase is an enzyme that is also present in the muscles. The alanine transaminase test should therefore be matched against an aspartate transaminase test for confirmation along with an ELISA test for the hepatitis virus.
Alanine transaminase comes into play in the alanine cycle by breaking down alpha ketoglutarate and alanine to form pyruvate and glutamate. This pyruvate is then set to the cells as a fuel. This cycle comes into play along with the more efficient Cori cycle in muscular activity. When our muscles are performing work, they are burning off glycogen. As long as there is sufficient oxygen in the muscles, all is well but at some point, they will be doing more work than the oxygen can be supplied to fuel the reaction. This is when lactic acid is produced which is toxic to the cells. This lactic acid is what causes muscle pain forcing us to stop the work. In the meantime, the lactic acid is sent to the liver and converted back to pyruvate in the Cori cycle. In the alanine cycle, the same reaction occurs but not as efficiently and one of the byproducts of the alanine cycle is the production of ammonia and urea. It is therefore, required to be performed when ammonia has to be moved out of the muscles.
Since the enzyme does exist in the muscles as well. Muscle wasting or disease can be judged with alanine transferase’s elevated levels but this has to be matched against a creatine kinase test to be absolutely sure. Creatine kinase is an enzyme that is responsible for energy conversion as well and its elevated levels indicate wastage of muscle in the body.