What is the Difference Between SGOT and SGPT

The key difference between SGOT and SGPT is that SGOT catalyzes the transfer of an α-amino group from L-aspartate to α-ketoglutarate in order to produce oxaloacetate and L-glutamate while SGPT catalyzes the transfer of an α-amino group from L-alanine to α-ketoglutarate to produce pyruvate and L-glutamate.

SGOT level and SGPT level and their ratio (SGOT/SGPT) are commonly measured as biomarkers in the clinical setup for liver health. These tests are part of blood panels. Moreover, these tests are generally called liver functions tests. Therefore, SGOT level and SGPT level and their ratio (SGOT/SGPT) are useful biomarkers of liver injury in a patient with some degree of intact liver function.

CONTENTS

1. Overview and Key Difference
2. What is SGOT  
3. What is SGPT
4. Similarities – SGOT and SGPT
5. SGOT vs SGPT in Tabular Form
6. Summary – SGOT vs SGPT

What is SGOT (Serum Glutamic Oxaloacetic Transaminase)?

Serum glutamic oxaloacetic transaminase (SGOT) is an enzyme that catalyzes the interconversion of aspartate and α-ketoglutarate to oxaloacetate and glutamate. It is also known as aspartate transaminase (AST). This enzyme is a pyridoxal phosphate (PLP) dependent transaminase enzyme. SGOT was first discovered by Arthur Karmen and colleagues in 1954. Moreover, this enzyme catalyzes the reversible transfer of an α-amino group from L-aspartate to α-ketoglutarate in order to produce oxaloacetate and L-glutamate. Therefore, it is a very important enzyme in amino acid metabolism. SGOT is normally found in the liver, heart, skeletal muscle, kidneys, brain, red blood cells, and gall bladder. SGOT level and SGPT level and their ratio (SGOT/SGPT) are commonly measured as biomarkers for liver health.

The half-life of the total SGOT in the circulation is approximately around 17 hours. On average 87 hours for mitochondrial SGOT. Furthermore, SGOT is cleared by sinusoidal cells in the liver. There are two SGOT isoenzymes present in a wide variety of eukaryotes. In humans, they are GOT1/cAST (cytosolic isoenzyme derives mainly from red blood cells and heart) and GOT2/mAST (the mitochondrial isoenzyme which is present predominantly in the liver). Clinically elevated SGOT levels can be seen in diseases such as myocardial infarction, acute pancreatitis, acute haemolytic anemia, severe burns, acute renal disease, musculoskeletal diseases, and trauma. Furthermore, SGOT/SGPT ratio greater than 2 is suggestive of alcoholic hepatitis and cirrhosis.

What is SGPT (Serum Glutamic Pyruvic Transaminase)?

Serum glutamic pyruvic transaminase (SGPT) is an enzyme that catalyzes the transfer of an α-amino group from L-alanine to α-ketoglutarate to produce pyruvate and L-glutamate. It is also known as alanine aminotransferase (ALT). SGPT was first characterized in 1950 by Arthur Karmen and colleagues. SGPT is found in plasma and in various body tissues. But predominantly, it is found in the liver.

The half-life of SGPT in the circulation is approximately around 47 hours. SGPT is cleared by the sinusoidal cells in the liver. SGPT also requires the coenzyme pyridoxal phosphate, which is converted to pyridoxamine during the reversible transamination reaction. Furthermore, significantly elevated level of ALT often suggests the existence of medical conditions such as viral hepatitis, diabetes, congestive heart failure, liver damage, bile duct problems, infectious mononucleosis, and myopathy.

What are the Similarities Between SGOT and SGPT?

• SGOT level and SGPT level and their ratio (SGOT/SGPT) are useful biomarkers of liver injury in a patient with some degree of intact liver function.
• Both enzymes are proteins made up of amino acids.
• These enzymes have clinical significance in diagnosing diseases.
• Both enzymes need pyridoxal phosphate (PLP) as a coenzyme.
• These enzymes are originally discovered by Arthur Karmen and colleagues.
• They catalyze reversible transamination reactions.

What is the Difference Between SGOT and SGPT?

SGOT catalyzes the transfer of an α-amino group from L-aspartate to α-ketoglutarate in order to produce oxaloacetate and L-glutamate while SGPT catalyzes the transfer of an α-amino group from L-alanine to α-ketoglutarate to produce pyruvate and L-glutamate. Thus, this is the key difference between SGOT and SGPT.

The below infographic presents the differences between SGOT and SGPT in tabular form for side by side comparison.

Summary – SGOT vs SGPT

SGOT and SGPT are useful biomarkers of liver injury in a patient with some degree of intact liver function. They have clinical significance in diagnosing other diseases as well. SGOT catalyzes the transfer of an α-amino group from L-aspartate to α-ketoglutarate in order to produce oxaloacetate and L-glutamate while SGPT catalyzes the transfer of an α-amino group from L-alanine to α-ketoglutarate to produce pyruvate and L-glutamate. So, this summarizes the difference between SGOT and SGPT.

Reference:

1. Lin JD;Lin PY;Chen LM;Fang WH;Lin LP;Loh CH; “Serum Glutamic-Oxaloacetic Transaminase (Got) and Glutamic-Pyruvic Transaminase (GPT) Levels in Children and Adolescents with Intellectual Disabilities.” Research in Developmental Disabilities, U.S. National Library of Medicine.
2. “NCI Dictionary of Cancer Terms.” National Cancer Institute.

Image Courtesy:

1. “Liver enzyme diagram” By Elliott.jd – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Alanine transaminase reaction” By Akane700 – Own work (CC BY-SA 3.0) via Commons Wikimedia