Serum glutamate pyruvate transaminase

Enzyme involved in amino acid metabolism

  [[File:|frameless|alt=]]

Structure of ALT enzyme

Identifiers
EC number	2.6.1.2
CAS number	9000-86-6
Alt. names
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway

Serum glutamate pyruvate transaminase (SGPT), also known as alanine aminotransferase (ALT), is an enzyme primarily found in the liver. It plays a crucial role in the metabolism of amino acids, specifically in the transamination process where it catalyzes the conversion of alanine and α-ketoglutarate to pyruvate and glutamate.

Function

SGPT/ALT is a key enzyme in the Cahill cycle, which is important for the gluconeogenic pathway. This enzyme facilitates the transfer of an amino group from alanine to α-ketoglutarate, forming pyruvate and glutamate. Pyruvate can then enter the citric acid cycle or be used in the synthesis of glucose, while glutamate can be further metabolized or used in the synthesis of other amino acids.

Clinical significance

SGPT/ALT is commonly measured in blood tests as a marker of liver health. Elevated levels of ALT in the blood can indicate liver damage or inflammation, as the enzyme is released into the bloodstream when liver cells are damaged. Conditions that can cause elevated ALT levels include hepatitis, cirrhosis, non-alcoholic fatty liver disease, and liver cancer.

Measurement

ALT levels are measured in units per liter (U/L) of blood. Normal ranges can vary slightly depending on the laboratory, but they are generally between 7 and 56 U/L. It is important to interpret ALT levels in the context of other liver function tests, such as aspartate transaminase (AST), alkaline phosphatase, and bilirubin.

History

The enzyme was first described in the 1950s, and its clinical significance was recognized soon after. The development of automated blood chemistry analyzers in the 1970s made it possible to routinely measure ALT levels in clinical settings.

See also

• Aspartate transaminase
• Liver function tests
• Hepatology
• Transaminase