After listening to Mr. Liu's account, I patiently explained to him that transaminase is a group of aminotransferases involved in intracellular protein metabolism, present in almost all organs and tissue cells of the human body. However, the liver is the most enzyme-rich organ in the human body, with enzyme proteins accounting for about two-thirds of the total liver protein content. There are more than 20 types of transaminases in the human body, and the main ones used for serum diagnosis in clinical practice are Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST).
ALT, formerly known as Glutamic Pyruvic Transaminase (commonly referred to as "GPT"), has now been officially named Alanine Aminotransferase by the World Health Organization (WHO). This enzyme is mainly found in the cytoplasm of liver cells. Since its activity in the liver is about 100 times higher than in serum, even if only 1% of liver cells die, it can double the ALT level in serum. Therefore, it is one of the most sensitive indicators for liver function tests.
AST, formerly known as Glutamic Oxaloacetic Transaminase (commonly referred to as "GOT"), has now been officially named Aspartate Aminotransferase by WHO. This enzyme is most abundant in cardiac muscle, followed by the liver. When there is liver damage, its leakage rate is lower than that of ALT.
Generally, when there is substantial liver damage, some enzymes escape in large quantities from the damaged liver cells, while others remain in the blood due to poor liver function, causing the activity of these enzymes in serum to increase. Additionally, some enzymes decrease in production when liver cells are diseased. Therefore, changes in the activity of serum enzymes can reflect the pathological state of the liver.