Alanine transaminase

Diagram of alanine transaminase structure

Alanine transaminase (ALT), also known as serum glutamate-pyruvate transaminase (SGPT), is an enzyme primarily found in the liver. It plays a crucial role in the alanine cycle, which is important for amino acid metabolism and gluconeogenesis.

Function

ALT catalyzes the reversible transfer of an amino group from alanine to _-ketoglutarate, producing pyruvate and glutamate. This reaction is a key step in the catabolism of amino acids and is essential for the metabolism of nitrogen-containing compounds.

Clinical Significance

ALT is commonly measured in blood tests as a marker of liver function. Elevated levels of ALT in the bloodstream can indicate liver damage or liver disease, such as hepatitis, cirrhosis, or liver cancer.

Liver Diseases

In conditions like hepatitis, the liver cells are damaged, releasing ALT into the bloodstream. Monitoring ALT levels can help assess the extent of liver damage and the effectiveness of treatment.

Other Conditions

While ALT is most commonly associated with liver health, elevated levels can also be seen in conditions affecting other organs, such as heart failure or muscle injury.

Measurement

ALT levels are measured using a blood test. The normal range for ALT varies slightly between laboratories, but it is generally between 7 and 56 units per liter of serum. Factors such as age, gender, and body mass index can influence ALT levels.

Related Enzymes

ALT is part of a group of enzymes known as transaminases, which also includes aspartate transaminase (AST). Both ALT and AST are used in conjunction to assess liver health, with the ALT/AST ratio providing additional diagnostic information.

Related Pages

• Liver function tests
• Hepatitis
• Cirrhosis
• Transaminase
• Amino acid metabolism