Enolase

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Revision as of 11:01, 24 November 2014

Yeast enolase dimer complex with phosphoenolpyruvate and phosphoglycerate, 1one

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is an enzyme that catalyzes a reaction of glycolysis. Glycolysis converts glucose into two 3-carbon molecules called pyruvate. The energy released during glycolysis is used to make ATP.^[1] Enolase is used to convert 2-phosphoglycerate (2PG) to phosphoenolpyruvate (PEP) in the 9th reaction of glycolysis: it is a reversible dehydration reaction.^[2]. Enolase is expressed abundantly in most cells and has been proven useful as a model to study mechanisms of enzyme action and structural analysis ^[3]. As with the reaction below, Enolase must have a divalent metal cation present to activate or deactivate the enzyme. The best cofactor would be Mg2+, but many, including Zn2+, Mn2+ and Co2+ can be used. The metal ion works by binding to the enzyme at the active site and producing a conformational change. This makes it possible for the substrate (2-PGA) to bind at the Enolase active site. Once this happens, a second metal ion comes in and binds to the enzyme to activate the Enolase catalytic ability. For sequence alignment see Enolase multiple sequence alignment.

1 Structure
2 Mechanism
3 Kinetics
4 Regulation
5 Other interesting information
6 3D structures of enolase
7 Additional Resources

Structure

The of enolase contains both alpha helices and beta sheets. The beta sheets are mainly parallel^[4]. As shown in the figure, enolase has about 36 alpha helices and 22 beta sheets (18 alpha helices and 11 beta sheets per domain). Enolase consists of two domains.

Structural Clasification of Proteins (SCOP)^[5]

Enolase is in the alpha and beta proteins class and has a fold of TIM beta/alpha-barrel. It comes from the Superfamily on Enolase C-terminal domain-like and is in the enolase family.

Mechanism

^[6]

The of enolase as shown, involves Lys 345, Lys 396, Glu 168, Glu 211, and His 159. Enolase forms a complex with two at its active site. The substrate, 2PG, binds to the two . The Mg 2+ then forms a bond at the deprotonated carboxylic acid on the 1'C to connect it with enolase. It also is connects to Glu 211 and Lys 345. Glu 211 makes a hydrogen bond with the alcohol group on the 3'C. Lys 345 deprotonates the 2'C and then the 2'C forms an alkene with the 1'C which then moves the electrons forming the ketone onto the oxygen making it have a negative charge. The other oxygen, which already has a negative charge, then moves its electron to form a ketone with the 1'C. The electrons that made up the alkene between the 1'C adn 2'C then moves to form an alkene between the 2'C and 3'C. This breaks the bond with the alcohol on the 3'C which deprotonates Glu 211 on enolase to form H2O. Then the new molecule is released from enolase as PEP. PEP then goes on through another step in glycolysis to create pyruvate.

Fluoride ions inhibits glycolysis by forming a bond with Mg 2+ thus blocks the substrate (2PG) from binding to the active site of enolase.^[7]

Kinetics

^[8]

Since Mg2+ is essential for binding the substrate, 2-PG, it is also needed at a specific quality in order to have a good rate, or velocity. The graph shows the V vs. [PGA], in which PGA is 2-PG, with two different concentrations of Mg2+. The upper curve, which also has greater Vmax, has an Mg2+ concentration of 10^-3 M while the lower curve, which has a lower Vmax, has an Mg2+ concentration of 10^-2 M^[9]. The Km is also larger the upper curve making the higher [Mg2+] more desirable.

Regulation

Enolase is found on the surface of a variety of eukaryotic cells as a strong plamingoen-binding receptor and on the surface of hematopietic celss such as monocytes, T cells and B cells, neuronal celss and endothelial cells. Enolase in muscle can bind other glycolytic enzymes, such as phosphoglycerate mutase, muscle creatine kinase, pyruvate kinase, and muscle troponin, with high affinity. This suggests that they make a functional glycolytic segment in the muscle where ATP production is required in order for the muscle to contract. Myc-binding protein (MBP-1) is similar to the a-enolse structure and is found in the nucleus as a DNA-binding protein^[10]. Enolase is regulated by the concentration of Mg2+ and the previous steps of glycolysis.

Other interesting information

Enolase is present in all tissues and organisms with the ability to do glycolysis or fermentation. Recent studies have Enolase concentration samples in order to determine certain conditions and their severity. For instance, high concentrations of Enolase in cerebrospinal fluid (CSF) are more strongly associated with astrocytoma than other enzymes like aldolase, pyruvate kinase, and creatine kinase. High concentrations of Enolase in the CSF are also linked to the fastest rate of tumor growth and increased chances of heart attack or stroke. Enolase can be competitively inhibited by fluoride for the substrate 2-PGA. In drinking water with added fluorination, oral bacteria Enolase activity is inhibited without harmed humans. This works to prevent cavities.

3D structures of enolase

Updated on 24-November-2014

Additional Resources

For additional information, see: Carbohydrate Metabolism

References

↑ Voet, Donald, Judith G. Voet, and Charlotte W. Pratt. Fundamentals of Biochemistry: Life at the Molecular Level. 3rd ed. Hoboken, NJ: John Wiley & Sons, Inc., 2008.
↑ Voet, Donald, Judith G. Voet, and Charlotte W. Pratt. Fundamentals of Biochemistry: Life at the Molecular Level. 3rd ed. Hoboken, NJ: John Wiley & Sons, Inc., 2008.
↑ Pancholi, V. "Multifunctional a-Enolase: Its Role in Diseases." CMLS, Cellular and Molecular Life Sciences 58 (2001): 902-20.
↑ The scop authors. Structural Classification of Proteins. “Protein: Enolase from Baker's yeast (Saccharomyces cerevisiae). 2009. 2/26 2010. [<http://scop.mrc-lmb.cam.ac.uk/scop/data/scop.b.d.b.bc.b.b.html>.]
↑ The scop authors. Structural Classification of Proteins. “Protein: Enolase from Baker's yeast (Saccharomyces cerevisiae). 2009. 2/26 2010. [<http://scop.mrc-lmb.cam.ac.uk/scop/data/scop.b.d.b.bc.b.b.html>.]
↑ Nguyen, Tram, and Katelyn Thompson. "Mechanism of Enolase Converting 2-Phosphoglycerate to Phosphoenolpyruvate." ChemDraw 10.0: Public Domain, 2008. [1].
↑ Voet, Donald, Judith G. Voet, and Charlotte W. Pratt. Fundamentals of Biochemistry: Life at the Molecular Level. 3rd ed. Hoboken, NJ: John Wiley & Sons, Inc., 2008.
↑ Westhead, E. W., and BO G. Malmstrom. "The Chemical Kinetics of the Enolase Reaction with Special References to the Use of Mixed Solvents." The Journal of Biological Chemistry 228 (1957): 655-71.
↑ Westhead, E. W., and BO G. Malmstrom. "The Chemical Kinetics of the Enolase Reaction with Special References to the Use of Mixed Solvents." The Journal of Biological Chemistry 228 (1957): 655-71.
↑ Pancholi, V. "Multifunctional a-Enolase: Its Role in Diseases." CMLS, Cellular and Molecular Life Sciences 58 (2001): 902-20.

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Retrieved from "http://52.214.119.220/wiki/index.php/Enolase"

Category: Topic Page

@@ Line 32: / Line 32: @@
 Updated on {{REVISIONDAY2}}-{{MONTHNAME|{{REVISIONMONTH}}}}-{{REVISIONYEAR}}
+{{#tree:id=OrganizedByTopic|openlevels=0|
-===Enolase===
+*Enolase
-[[3dip]], [[2qgy]] – ENO – unidentified<BR />
+**[[3dip]], [[2qgy]] – ENO – unidentified<BR />
-[[1oep]] - TbENO – ''Trypanosoma brucei''<BR />
+**[[1oep]] - TbENO – ''Trypanosoma brucei''<BR />
-[[2ptw]] – TbENO (mutant) <BR />
+**[[2ptw]] – TbENO (mutant) <BR />
-[[2ptx]] - TbENO (mutant) + sulfate<BR />
+**[[2ptx]] - TbENO (mutant) + sulfate<BR />
-[[2pty]] - TbENO (mutant) + PEP<BR />
+**[[2pty]] - TbENO (mutant) + PEP<BR />
-[[2ptz]], [[2pu0]], [[2pu1]] - TbENO (mutant) + PAH<BR />
+**[[2ptz]], [[2pu0]], [[2pu1]] - TbENO (mutant) + PAH<BR />
-[[2pa6]] – ENO – ''Methanocaldococcus jannaschii''<BR />
+**[[2pa6]] – ENO – ''Methanocaldococcus jannaschii''<BR />
-[[1w6t]] – ENO – ''Streptococcus pneumoniae''<BR />
+**[[1w6t]] – ENO – ''Streptococcus pneumoniae''<BR />
-[[1iyx]] – ENO – ''Enterococcus hirae''<BR />
+**[[1iyx]] – ENO – ''Enterococcus hirae''<BR />
-[[1pdy]], [[1pdz]] – ENO – European lobster<br />
+**[[1pdy]], [[1pdz]] – ENO – European lobster<br />
-[[3qn3]] – ENO – ''Campylobacter jejuni''<br />
+**[[3qn3]] – ENO – ''Campylobacter jejuni''<br />
-[[3tqp]] – ENO – ''Coxiella burnetii''<br />
+**[[3tqp]] – ENO – ''Coxiella burnetii''<br />
-[[3ugv]] – ENO – ''Alpha proteobacterium''<br />
+**[[3ugv]] – ENO – ''Alpha proteobacterium''<br />
-[[4a3r]] – BsENO – ''Bacillus subtilis''<br />
+**[[4a3r]] – BsENO – ''Bacillus subtilis''<br />
-[[4h1z]] – ENO – ''Rhizobium meliloti''<br />
+**[[4h1z]] – ENO – ''Rhizobium meliloti''<br />
-[[4jn7]], [[4jn8]] – ENO – ''Agrobacterium radiobacter''<br />
+**[[4jn7]], [[4jn8]] – ENO – ''Agrobacterium radiobacter''<br />
-[[3zlf]], [[3zlg]], [[3zlh]] - ENO (mutant) – ''Streptococcus pyogenes''<br />
+**[[3zlf]], [[3zlg]], [[3zlh]] - ENO (mutant) – ''Streptococcus pyogenes''<br />
-[[4g7f]] - ENO – ''Trypanosoma cruzi''<br />
+**[[4g7f]] - ENO – ''Trypanosoma cruzi''<br />
-[[4gir]], [[4gis]] - ENO – ''Vibrio harveyi''<br />
+**[[4gir]], [[4gis]] - ENO – ''Vibrio harveyi''<br />
-===Enolase 1===
+*Enolase 1
-[[3b97]], [[2psn]] – hENO1 - human<BR />
+**[[3b97]], [[2psn]] – hENO1 - human<BR />
-[[3otr]] – ENO1 – ''Toxoplasma gondii''<BR />
+**[[3otr]] – ENO1 – ''Toxoplasma gondii''<BR />
-[[3qtp]] – ENO1 – ''Entamoeba histolytica''<br />
+**[[3qtp]] – ENO1 – ''Entamoeba histolytica''<br />
-[[1e9i]] - EcENO1 – ''Escherichia coli''<BR />
+**[[1e9i]] - EcENO1 – ''Escherichia coli''<BR />
-[[2xgz]], [[2xh0]], [[2xh2]], [[2xh4]], [[2xh7]] – EcENO1 residues 2-437 (mutant) <BR />
+**[[2xgz]], [[2xh0]], [[2xh2]], [[2xh4]], [[2xh7]] – EcENO1 residues 2-437 (mutant) <BR />
-[[3uj2]] – ENO1 – ''Anaerostipes caccae''<br />
+**[[3uj2]] – ENO1 – ''Anaerostipes caccae''<br />
-[[3h8a]], [[2fym]] – EcENO1 + RNase E<BR />
+**[[3h8a]], [[2fym]] – EcENO1 + RNase E<BR />
-[[3enl]], [[4enl]] – yENO1 - yeast<BR />
+**[[3enl]], [[4enl]] – yENO1 - yeast<BR />
-[[2al1]], [[2al2]], [[1ebh]] – yENO1 + Mg<BR />
+**[[2al1]], [[2al2]], [[1ebh]] – yENO1 + Mg<BR />
-[[1p43]], [[1p48]] – yENO1 (mutant) <BR />
+**[[1p43]], [[1p48]] – yENO1 (mutant) <BR />
-[[1ebg]], [[1els]] - yENO1 + PAH<BR />
+**[[1ebg]], [[1els]] - yENO1 + PAH<BR />
-[[1l8p]] - yENO1 (mutant) + PAH<BR />
+**[[1l8p]] - yENO1 (mutant) + PAH<BR />
-[[2one]], [[1one]] – yENO1 + PEP + phosphoglycerate<BR />
+**[[2one]], [[1one]] – yENO1 + PEP + phosphoglycerate<BR />
-[[5enl]], [[7enl]] - yENO1 + phosphoglycerate<BR />
+**[[5enl]], [[7enl]] - yENO1 + phosphoglycerate<BR />
-[[1nel]], [[6enl]] – yENO1 + inhibitor
+**[[1nel]], [[6enl]] – yENO1 + inhibitor
-===Enolase 2===
+*Enolase 2
-[[4ewj]] – ENO2 – ''Streptococcus suis''
+**[[4ewj]] – ENO2 – ''Streptococcus suis''
-===Enolase 3===
+*Enolase 3
-[[2xsx]] - hENO3
+**[[2xsx]] - hENO3
-===γ Enolase (neuron specific enolase)===
+*γ Enolase (neuron specific enolase)
-[[1te6]], [[3ucc]], [[3ucd]], [[3uje]], [[3ujf]], [[3ujr]], [[3ujs]] – hENOγ<BR />
+**[[1te6]], [[3ucc]], [[3ucd]], [[3uje]], [[3ujf]], [[3ujr]], [[3ujs]] – hENOγ<BR />
-[[2akm]], [[2akz]] – hENOγ + inhibitor<br />
+**[[2akm]], [[2akz]] – hENOγ + inhibitor<br />
-===2, 3-diketo-5-methylthiopentyl-1-phosphate enolase===
+*2, 3-diketo-5-methylthiopentyl-1-phosphate enolase
-[[2zvi]] – DK-MTP-1-P BsENO <br />
-[[2oej]] - BkDK-MTP-1-P ENO + Pi – ''Geobacillus kaustophilus''<br />
-[[2oek]], [[2oel]] - BkDK-MTP-1-P ENO + ion<br />
-[[2oem]] - BkDK-MTP-1-P ENO + Mg + phosphate derivative
+**[[2zvi]] – DK-MTP-1-P BsENO <br />
+**[[2oej]] - BkDK-MTP-1-P ENO + Pi – ''Geobacillus kaustophilus''<br />
+**[[2oek]], [[2oel]] - BkDK-MTP-1-P ENO + ion<br />
+**[[2oem]] - BkDK-MTP-1-P ENO + Mg + phosphate derivative
+}}
 ==Additional Resources==
 For additional information, see: [[Carbohydrate Metabolism]]

Enolase

From Proteopedia

Revision as of 11:01, 24 November 2014

Contents

Structure

Mechanism

Kinetics

Regulation

Other interesting information

3D structures of enolase

Additional Resources

References

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