Neuron-specific enolase

Neuron-specific enolase
	Model according to 1TE6
	Existing structural data : 1TE6 , 2AKM , 2AKZ , 3UCC , 3UCD , 3UJE , 3UJF , 3UJR , 3UJS
Properties of human protein
Mass / length primary structure	433 amino acids
Secondary to quaternary structure	Homodimer, heterodimer
Cofactor	2 mg 2+
Isoforms	α / γ, γ / γ
Identifier
Gene names	ENO2 ; ENOG
External IDs	OMIM : 131360 ; UniProt : P09104 ; MGI : 95394 ; CAS number : 9014-08-8;
Enzyme classification
EC, category	4.2.1.11 , lyase
Response type	Elimination
Substrate	2-phospho-D-glycerate
Products	Phosphoenolpyruvate + H 2 O
Occurrence
Homology family	Enolase 3
Parent taxon	Creature
	Orthologue

The neuron-specific enolase (NSE, ENOG), Eng .: neuro specific enolase , is an enzyme (organic catalyst ) of the glucose metabolism . It occurs in various isoforms in the nerve cells (neurons) of the brain and peripheral nerve tissue as well as in neuroendocrine tissues , v. a. in the so-called APUD cells .

Elevated serum levels of NSE are the result of cardiovascular events, cerebral trauma , various tumor diseases, scleroderma, Creutzfeldt-Jakob disease or poor handling of blood samples due to the breakdown of erythrocytes or platelets. The upper limit value in the serum in adults is given differently by different laboratories as 10, 12, 16.3 and 18.5 μg / l.

NSE belongs to one of three groups of enzymes which are collectively referred to as enolases , all of which catalyze the same reaction and which are found in all living things that utilize glucose. While α-enolases are tissue-unspecific, β-enolases are only localized in muscle cells and γ-enolases only in nerve tissue. In fact, it is a homo- or heterodimer made up of three possible subunits (α, β, γ) that are combined with one another. Of these combinations, five are actually encountered: α / α in embryos and tissue-unspecific in adults; α / β and β / β in striated muscles; and α / γ and γ / γ in neurons. The heterodimers are preferably synthesized during ontogenesis .

Catalyzed reaction

		${\ displaystyle \ mathrm {\ xrightarrow [{Enolase}] {- water}}}$		ADP ATP pyruvate kinase
	D - 2-phosphoglycerate		Phosphoenolpyruvate		Pyruvate

2-phosphoglycerate splits off a water molecule; it arises phosphoenolpyruvate (PEP). Due to the resulting double bond , the phosphate group of PEP is bound unstably and is easily transferred to ADP with formation of ATP ; pyruvic acid or pyruvate is produced from the PEP .

rating

NSE for benign diseases

Increased concentrations of NSE in the blood serum are found in

benign lung disease
Diseases of the brain or nerve cells.

In diseases of the brain, increased values for NSE can also be found in the liquor (brain water). This applies e.g. B. for meningitis ( meningitis ), stroke , intracerebral hemorrhage , subarachnoid hemorrhage , cerebral hypoxia (insufficient supply of oxygen), encephalomyelitis disseminata (multiple sclerosis), Creutzfeldt-Jakob disease and other diseases that lead to the degeneration of nerve cells. NSE is a prognostic factor for patients with cerebral hypoxia. Significantly increased NSE values in the serum (> 33 μg / l) in the first few days after resuscitation indicate an unfavorable prognosis.

Pregnancies with neural tube defects in the child

NSE in malignant diseases

NSE is a tumor marker for very different tumors. In small cell lung cancer , NSE is the central tumor marker; it correlates with the extent of the disease, but not with the location and type of metastasis. Successful chemotherapy leads to a decrease in the initially elevated NSE values. NSE increases can also be found in neuroblastoma , neuroendocrine tumors , seminoma (testicular tumor), Ewing's sarcoma, and with lower sensitivity in kidney cancer and other tumor diseases. NSE is not suitable for the search for tumors or for the initial diagnosis, but it is suitable for monitoring a course or a treatment.

Disruptions

NSE is found in higher concentrations in erythrocytes (red blood cells) and in thrombocytes (blood platelets). Therefore, increased NSE values are found in the serum when the red blood cells are destroyed (e.g. in the event of hemolysis ) or the blood platelets (e.g. in the event of undesired coagulation in the analysis tube or improper centrifugation).

Inhibitors

The enolase is inhibited by fluoride . This is used in blood samples if you want to determine the glucose values. Due to the inhibited enzyme, glycolysis cannot take place in the test tube, so that glucose does not break down.

Individual evidence

↑ PROSITE PDOC00148
↑ UniProt entry
↑ Entry on phosphoenolpyruvate. In: Römpp Online . Georg Thieme Verlag, accessed on April 14, 2011.
↑ Todd A. Swanson, Sandra I. Kim and Marc J. Glucksman: BRS Biochemistry, Molecular Biology, and Genetics . Lippincott Raven; 5th edition 2010; ISBN 978-0-7817-9875-4 ; P. 65

literature

Xuejun You: Clinical and molecular cytogenetic characterization of aesthetic neuroblastomas . Berlin 2002, DNB 965421600 , urn : nbn: de: kobv: 11-10017701 (dissertation).

Web links

Wikibooks: Biochemistry and Pathobiochemistry: Enolase - Learning and Teaching Materials

Deutsches Ärzteblatt

[1] PROSITE PDOC00148

[2] UniProt entry

[3] Entry on phosphoenolpyruvate. In: Römpp Online . Georg Thieme Verlag, accessed on April 14, 2011.

[4] Todd A. Swanson, Sandra I. Kim and Marc J. Glucksman: BRS Biochemistry, Molecular Biology, and Genetics . Lippincott Raven; 5th edition 2010; ISBN 978-0-7817-9875-4 ; P. 65