Alanine transaminase

  • CAS Number: 9000-86-6

The alanine aminotransferase ( ALT, ALT) (formerly: glutamate - pyruvate transaminase, GPT ) is an enzyme found mainly in the cytoplasm of liver cells. It requires for its function, the coenzyme pyridoxal phosphate (vitamin B6).

It catalyzes the reaction of L- alanine α -ketoglutarate = pyruvate L- glutamate.

This reaction takes place in the glucose -alanine cycle a significant role, with alanine is formed in the muscles of excess nitrogen and pyruvate by ALAT, transported in the blood to the liver and there by ALAT back to pyruvate ( for gluconeogenesis ) and nitrogen (for the urea cycle) is converted.

Laboratory diagnostics

In the laboratory diagnostics, the activity of ALAT from plasma or serum is determined in order to clarify whether a liver or biliary tract disease is present. The reference range for measurements at 37 ° C after IFCC is 50 U / L (units per liter). Increased ALAT values ​​indicate almost always on a liver disease out were harmed in the liver cells. For the interpretation of the other material liver function tests (bilirubin, alkaline phosphatase, AST / GOT and GGT) should be determined.

Slight increases are found in fatty liver, liver tumors, liver metastases, liver cell necrosis, cholangitis, gallbladder removal and cholecystectomy by drugs or alcohol. Stronger increases are found in all chronic hepatitis, liver cirrhosis, hepatic congestion or toxic liver damage ( for example, by fungal toxins ). In acute hepatitis, the ALT may rise to more than 5000 U / l. In addition, a short-term increase in myocardial infarction occurs.

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