Skeletal muscle transaminase activities

While considerable amounts of both GOT and GPT are found in cardiac muscle, skeletal muscle and kidney, differential diagnosis is aided by the fact that the liver shows a much higher total GPT activity. An important clinical application of measurements of transaminase activity is the detection and diagnosis of viral... 

Glucocorticoids also increase the activity of transaminases (aminotransferases), especially in the skeletal muscle. Aminotransferases serve to transfer the amino groups from amino acids to be metabolized to a-keto acids, especially pyruvate. In the latter case, the alanine thus formed is transported from the muscle into the bloodstream and extracted from there by the liver. In the liver, alanine is converted to glucose, and glucose may then return to the muscle as it does in the Cori cycle (Figure 18.4). This is the alanine cycle, and more about this is discussed in Chapter 20. Branched-chain amino acids are the principal donors of nitrogen to pyruvate in the muscle and are thus important actors in the alanine cycle. 

Transamination reactions combine reversible amina-tion and deamination, and they mediate redistribution of amino groups among amino acids. Transaminases (aminotransferases) are widely distributed in human tissues and are particularly active in heart muscle, liver, skeletal muscle, and kidney. The general reaction of transamination is... 

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