Glucose-6-phosphate isomerase

Glucose-6-phosphate isomerase (GPI), also known as phosphoglucose isomerase (PGI) or phosphohexose isomerase (PHI), is an enzyme that in humans is encoded by the GPI gene. It is involved in both the glycolysis and gluconeogenesis metabolic pathways.

Function

Glucose-6-phosphate isomerase is an enzyme that catalyzes the conversion of glucose-6-phosphate into fructose 6-phosphate in the second step of glycolysis. This reaction is reversible and can therefore function in both glycolysis and gluconeogenesis.

Structure

The GPI enzyme is a monomer that folds into two domains, the larger of which contains a deep cleft where the catalytic residues are located. The active site is located in the cleft and is composed of three residues: His388, Glu357, and Glu297.

Clinical significance

Deficiencies in GPI are associated with hemolytic anemia, which is characterized by the destruction of red blood cells. This condition is inherited in an autosomal recessive manner.

See also

• Glycolysis
• Gluconeogenesis
• Enzyme
• Glucose-6-phosphate
• Fructose 6-phosphate

References

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