2-Phospho-D-glycerate <=> Phosphoenolpyruvate + H2O

Stable Identifier
Reaction [transition]
Homo sapiens
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Cytosolic enolase catalyzes the reversible reaction of 2 phosphoglycerate to form phosphoenolpyruvate and water, elevating the transfer potential of the phosphoryl group.

Enolase is a homodimer and requires Mg++ for activity. Three isozymes have been purified and biochemically characterized. The alpha isoform is expressed in many normal human tissues (Giallongo et al. 1986). The beta isoform is expressed in muscle. Evidence for its function in vivo in humans comes from studies of a patient in whom a point mutation in the gene encoding the enzyme was associated specifically with reduced enolase activity in muscle extracts and with other symptoms consistent with a defect in glycolysis (Comi et al. 2001). The gamma isoform of human enolase is normally expressed in neural tissue and is of possible clinical interest as a marker of some types of neuroendocrine and lung tumors (McAleese et al. 1988). Biochemical studies of the homologous rat proteins indicate that both homo- and heterodimers of enolase form and are enzymatically active (Rider and Taylor 1974).

A fourth candidate isozyme, ENO4, has been identified in the human and mouse genomes. The mouse form of the gene encodes a protein with enolase activity that is expressed in sperm and whose disruption is associated with abnormal sperm morphology (Nakamura et al. 2013).

Literature References
PubMed ID Title Journal Year
4413246 Enolase isoenzymes in rat tissues. Electrophoretic, chromatographic, immunological and kinetic properties

Rider, CC, Taylor, CB

Biochim Biophys Acta 1974
3208766 Complete amino acid sequence of the neurone-specific gamma isozyme of enolase (NSE) from human brain and comparison with the non-neuronal alpha form (NNE)

Dunbar, B, Day, IN, McAleese, SM, Fothergill, JE, Hinks, LJ

Eur J Biochem 1988
2462567 Tau-crystallin/alpha-enolase: one gene encodes both an enzyme and a lens structural protein

Stapel, SO, de Jong, WW, Williams, LA, Lietman, T, Wistow, GJ, Piatigorsky, J, Horwitz, J

J Cell Biol 1988
3529090 Molecular cloning and nucleotide sequence of a full-length cDNA for human alpha enolase

Croce, CM, Giallongo, A, Feo, S, Showe, LC, Moore, R

Proc Natl Acad Sci U S A 1986
23446454 Disruption of a spermatogenic cell-specific mouse enolase 4 (eno4) gene causes sperm structural defects and male infertility

Eddy, EM, Willis, WD, Dai, Q, Nakamura, N, Brown, PR, Goulding, EH, Williams, J

Biol Reprod 2013
11506403 Beta-enolase deficiency, a new metabolic myopathy of distal glycolysis

Bresolin, N, Jann, S, Prelle, A, Scarlato, G, Ciscato, P, Torrente, Y, Galbiati, S, Fortunato, F, Lucchiari, S, Chiveri, L, Keller, A, Bordoni, A, Comi, GP

Ann Neurol 2001
Catalyst Activity

phosphopyruvate hydratase activity of enolase dimer [cytosol]

Orthologous Events
Cross References
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