Alpha-enolase

Alpha-enolase (also known as ENO1) is an enzyme that in humans is encoded by the ENO1 gene. It is one of three enolase isoenzymes found in mammals; this isoenzyme is found in most tissues in the body, and a homodimer composed of two alpha subunits constitutes the most common form.

Function

Alpha-enolase is a glycolytic enzyme that catalyzes the conversion of 2-phosphoglycerate (2-PG) to phosphoenolpyruvate (PEP), a key step in the glycolysis pathway. This reaction involves the abstraction of a proton from the 2-carbon of 2-PG to form a carbonyl group, followed by the transfer of a phosphate group from the 3-carbon to the 2-carbon to form PEP.

Clinical significance

Alpha-enolase has been identified as an autoantigen in severe forms of autoimmune diseases, such as rheumatoid arthritis and Hashimoto's encephalopathy. It is also overexpressed in several types of cancer, including lung cancer, breast cancer, and colorectal cancer, and has been suggested as a potential biomarker for these conditions.

See also

• Enolase
• Glycolysis
• Autoimmune disease
• Biomarker

External links

• ENO1 at the National Center for Biotechnology Information

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Glycolysis metabolic pathway

Glucose Hexokinase ATP ADP Glucose 6-phosphate Glucose-6-phosphate isomerase Fructose 6-phosphate Phosphofructokinase-1 ATP ADP Fructose 1,6-bisphosphate Fructose-bisphosphate aldolase Dihydroxyacetone phosphate + + Glyceraldehyde 3-phosphate Triosephosphate isomerase 2 × Glyceraldehyde 3-phosphate 2 ×  Glyceraldehyde-3-phosphate dehydrogenase NAD++ Pi NADH + H+ NAD++ Pi NADH + H+ 2 × 1,3-Bisphosphoglycerate 2 ×  Phosphoglycerate kinase ADP ATP ADP ATP 2 × 3-Phosphoglycerate 2 ×  Phosphoglycerate mutase 2 × 2-Phosphoglycerate 2 ×  Phosphopyruvate hydratase (enolase)   H2O   H2O 2 × Phosphoenolpyruvate 2 ×  Pyruvate kinase ADP ATP 2 × Pyruvate 2 ×