Alpha-glucan lyases - Revision history

Spencer Williams at 11:44, 30 April 2013

2013-04-30T11:44:19Z

Spencer Williams at 11:44, 30 April 2013

2013-04-30T11:44:07Z

Harry Brumer: updated citation keys

2013-04-15T19:22:08Z

updated citation keys

Spencer Williams at 04:26, 15 April 2013

2013-04-15T04:26:44Z

Spencer Williams at 11:38, 5 July 2010

2010-07-05T11:38:56Z

Harry Brumer: added Curator approved tag

2010-01-17T14:12:45Z

added Curator approved tag

Harry Brumer at 23:33, 27 July 2009

2009-07-27T23:33:57Z

Spencer Williams: New page: * Author: Stephen Withers * Responsible Editor: Spencer Williams ---- The alpha glucan lyases of Glycoside Hydrolase Family 31 degrade starch...

2009-07-15T10:24:47Z

New page: * Author: Stephen Withers * Responsible Editor: Spencer Williams ---- The alpha glucan lyases of Glycoside Hydrolase Family 31 degrade starch...

New page

* Author: [[User:Withers|Stephen Withers]]
* Responsible Editor: [[User:SpencerWilliams|Spencer Williams]]
----
The alpha glucan lyases of [[Glycoside Hydrolase Family 31]] degrade starch via an elimination mechanism, rather than via hydrolysis, forming an unsaturated (enol) product that quickly tautomerises to its keto form, 1,5-anhydro fructose.

[[Image:A-glucan_lyase.png|centre]]

The first half of their mechanism resembles that of [[Glycoside Hydrolase Family 31]] retaining alpha-glycosidases, and involves the formation of a covalent glycosyl-enzyme intermediate. Instead of hydrolyzing, this intermediate then decomposes through a syn-elimination mechanism, again via oxocarbenium ion-like transition states, as shown below. This mechanism was demonstrated through a combination of studies involving intermediate trapping, kinetic isotope effects and linear free energy relationships <cite>1</cite><cite>2</cite>.

[[Image:a-glucan lyase mechanism.png|centre]]
== References ==
<biblio>

#1 pmid=14596624
#2 pmid=15237973

</biblio>
[[Category:Definitions and explanations]]

@@ Line 5: / Line 5: @@
 The alpha glucan lyases of [[Glycoside Hydrolase Family 31]] degrade starch via an elimination mechanism, rather than via hydrolysis, forming an unsaturated (enol) product that quickly tautomerises to its keto form, 1,5-anhydro fructose.
-[[Image:A-glucan_lyase.png|center|600px]]
+[[Image:A-glucan_lyase.png|center|500px]]
 The first half of their mechanism resembles that of [[Glycoside Hydrolase Family 31]] retaining alpha-glycosidases, and involves the formation of a covalent glycosyl-enzyme [[intermediate]]. Instead of hydrolyzing, this intermediate then decomposes through a syn-elimination mechanism, again via [[oxocarbenium ion]]-like [[transition state]]s, as shown below. This mechanism was demonstrated through a combination of studies involving [[intermediate]] trapping, kinetic isotope effects and linear free energy relationships <cite>Lee2003 Yip2004</cite>.

@@ Line 5: / Line 5: @@
 The alpha glucan lyases of [[Glycoside Hydrolase Family 31]] degrade starch via an elimination mechanism, rather than via hydrolysis, forming an unsaturated (enol) product that quickly tautomerises to its keto form, 1,5-anhydro fructose.
-[[Image:A-glucan_lyase.png|thumb|center|600px]]
+[[Image:A-glucan_lyase.png|center|600px]]
 The first half of their mechanism resembles that of [[Glycoside Hydrolase Family 31]] retaining alpha-glycosidases, and involves the formation of a covalent glycosyl-enzyme [[intermediate]]. Instead of hydrolyzing, this intermediate then decomposes through a syn-elimination mechanism, again via [[oxocarbenium ion]]-like [[transition state]]s, as shown below. This mechanism was demonstrated through a combination of studies involving [[intermediate]] trapping, kinetic isotope effects and linear free energy relationships <cite>Lee2003 Yip2004</cite>.
-[[Image:a-glucan lyase mechanism.png|thumb|center|600px]]
+[[Image:a-glucan lyase mechanism.png|center|600px]]
 == References ==
 <biblio>

@@ Line 7: / Line 7: @@
 [[Image:A-glucan_lyase.png|thumb|center|600px]]
-The first half of their mechanism resembles that of [[Glycoside Hydrolase Family 31]] retaining alpha-glycosidases, and involves the formation of a covalent glycosyl-enzyme [[intermediate]]. Instead of hydrolyzing, this intermediate then decomposes through a syn-elimination mechanism, again via [[oxocarbenium ion]]-like [[transition state]]s, as shown below. This mechanism was demonstrated through a combination of studies involving [[intermediate]] trapping, kinetic isotope effects and linear free energy relationships <cite>1</cite><cite>2</cite>.
+The first half of their mechanism resembles that of [[Glycoside Hydrolase Family 31]] retaining alpha-glycosidases, and involves the formation of a covalent glycosyl-enzyme [[intermediate]]. Instead of hydrolyzing, this intermediate then decomposes through a syn-elimination mechanism, again via [[oxocarbenium ion]]-like [[transition state]]s, as shown below. This mechanism was demonstrated through a combination of studies involving [[intermediate]] trapping, kinetic isotope effects and linear free energy relationships <cite>Lee2003 Yip2004</cite>.
 [[Image:a-glucan lyase mechanism.png|thumb|center|600px]]
@@ Line 13: / Line 13: @@
 <biblio>
-#1 pmid=14596624
+#Lee2003 pmid=14596624
-#2 pmid=15237973
+#Yip2004 pmid=15237973
 </biblio>
 [[Category:Definitions and explanations]]

← Older revision		Revision as of 14:12, 17 January 2010
Line 1:		Line 1:
		+	{{CuratorApproved}}
	* Author: [[User:Withers\|Stephen Withers]]		* Author: [[User:Withers\|Stephen Withers]]
	* Responsible Curator: [[User:SpencerWilliams\|Spencer Williams]]		* Responsible Curator: [[User:SpencerWilliams\|Spencer Williams]]

@@ Line 7: / Line 7: @@
 [[Image:A-glucan_lyase.png|centre]]
-The first half of their mechanism resembles that of [[Glycoside Hydrolase Family 31]] retaining alpha-glycosidases, and involves the formation of a covalent glycosyl-enzyme intermediate. Instead of hydrolyzing, this intermediate then decomposes through a syn-elimination mechanism, again via oxocarbenium ion-like transition states, as shown below. This mechanism was demonstrated through a combination of studies involving intermediate trapping, kinetic isotope effects and linear free energy relationships <cite>1</cite><cite>2</cite>.
+The first half of their mechanism resembles that of [[Glycoside Hydrolase Family 31]] retaining alpha-glycosidases, and involves the formation of a covalent glycosyl-enzyme [[intermediate]]. Instead of hydrolyzing, this intermediate then decomposes through a syn-elimination mechanism, again via [[oxocarbenium ion]]-like [[transition state]]s, as shown below. This mechanism was demonstrated through a combination of studies involving [[intermediate]] trapping, kinetic isotope effects and linear free energy relationships <cite>1</cite><cite>2</cite>.
 [[Image:a-glucan lyase mechanism.png|centre]]

@@ Line 1: / Line 1: @@
 * Author: [[User:Withers|Stephen Withers]]
-* Responsible Editor:  [[User:SpencerWilliams|Spencer Williams]]
+* Responsible Curator:  [[User:SpencerWilliams|Spencer Williams]]
 ----
 The alpha glucan lyases of [[Glycoside Hydrolase Family 31]] degrade starch via an elimination mechanism, rather than via hydrolysis, forming an unsaturated (enol) product that quickly tautomerises to its keto form, 1,5-anhydro fructose.