6-Phosphogluconate dehydrogenase: Difference between revisions

Latest revision as of 01:54, 17 February 2025

Enzyme involved in the pentose phosphate pathway

6-Phosphogluconate dehydrogenase

6-Phosphogluconate dehydrogenase is an enzyme that plays a crucial role in the pentose phosphate pathway, a metabolic pathway parallel to glycolysis. This enzyme catalyzes the oxidative decarboxylation of 6-phosphogluconate to ribulose 5-phosphate, producing NADPH in the process.

Structure[edit]

6-Phosphogluconate dehydrogenase is a dimeric enzyme, meaning it consists of two subunits. Each subunit contains a binding site for the substrate, 6-phosphogluconate, and a binding site for the cofactor NADP+. The enzyme's structure allows it to facilitate the transfer of electrons from 6-phosphogluconate to NADP+, reducing it to NADPH.

Function[edit]

The primary function of 6-phosphogluconate dehydrogenase is to catalyze the conversion of 6-phosphogluconate into ribulose 5-phosphate. This reaction is an important step in the oxidative phase of the pentose phosphate pathway, which is essential for the production of NADPH and ribose 5-phosphate. NADPH is a critical reducing agent used in various biosynthetic reactions, including fatty acid synthesis and the maintenance of glutathione in its reduced form.

Mechanism[edit]

The enzyme operates through an oxidative decarboxylation mechanism. Initially, 6-phosphogluconate binds to the active site of the enzyme. The enzyme then facilitates the transfer of a hydride ion from the substrate to NADP+, forming NADPH. This is followed by the decarboxylation of the substrate, releasing carbon dioxide and forming ribulose 5-phosphate.

Clinical significance[edit]

Deficiencies in 6-phosphogluconate dehydrogenase can lead to disruptions in the pentose phosphate pathway, affecting the production of NADPH. This can have downstream effects on cellular processes that rely on NADPH, such as the detoxification of reactive oxygen species. However, such deficiencies are rare compared to other enzyme deficiencies in the pathway, such as glucose-6-phosphate dehydrogenase deficiency.

Related pages[edit]

Gallery[edit]

Structure of 6-phosphogluconate dehydrogenase
Crystal structure of the enzyme

Structure of 6-Phosphogluconate dehydrogenase
Another view of 6-Phosphogluconate dehydrogenase

@@ Line 1: / Line 1: @@
-== 6-Phosphogluconate Dehydrogenase ==
+{{Short description|Enzyme involved in the pentose phosphate pathway}}
+{{Enzyme}}
-[[File:PDB_1pgq_EBI.jpg|thumb|Structure of 6-phosphogluconate dehydrogenase]]
+'''6-Phosphogluconate dehydrogenase''' is an enzyme that plays a crucial role in the [[pentose phosphate pathway]], a metabolic pathway parallel to [[glycolysis]]. This enzyme catalyzes the oxidative decarboxylation of 6-phosphogluconate to [[ribulose 5-phosphate]], producing [[NADPH]] in the process.
-[[File:1pgo.jpg|thumb|Another view of the enzyme structure]]
-'''6-Phosphogluconate dehydrogenase''' is an enzyme that plays a crucial role in the [[pentose phosphate pathway]], a metabolic pathway parallel to [[glycolysis]]. This enzyme catalyzes the oxidative decarboxylation of 6-phosphogluconate to [[ribulose 5-phosphate]] and [[carbon dioxide]], with the concomitant reduction of [[NADP+]] to [[NADPH]].
+==Structure==
+-Phosphogluconate dehydrogenase is a [[dimeric enzyme]], meaning it consists of two subunits. Each subunit contains a binding site for the substrate, 6-phosphogluconate, and a binding site for the cofactor [[NADP+]]. The enzyme's structure allows it to facilitate the transfer of electrons from 6-phosphogluconate to NADP+, reducing it to NADPH.
-== Function ==
+==Function==
--Phosphogluconate dehydrogenase is involved in the oxidative phase of the pentose phosphate pathway. This pathway is essential for the production of [[NADPH]], which is required for [[biosynthetic reactions]] and for maintaining the [[redox balance]] in cells. The enzyme also contributes to the generation of [[ribose 5-phosphate]], a precursor for the synthesis of [[nucleotides]] and [[nucleic acids]].
+The primary function of 6-phosphogluconate dehydrogenase is to catalyze the conversion of 6-phosphogluconate into ribulose 5-phosphate. This reaction is an important step in the oxidative phase of the pentose phosphate pathway, which is essential for the production of NADPH and [[ribose 5-phosphate]]. NADPH is a critical reducing agent used in various biosynthetic reactions, including fatty acid synthesis and the maintenance of [[glutathione]] in its reduced form.
-== Structure ==
+==Mechanism==
-The enzyme is typically a dimer, with each subunit containing a binding site for NADP+ and 6-phosphogluconate. The active site of the enzyme is located at the interface between the two subunits, allowing for efficient catalysis. The structure of 6-phosphogluconate dehydrogenase has been elucidated through [[X-ray crystallography]], revealing details about its catalytic mechanism and substrate binding.
+The enzyme operates through an oxidative decarboxylation mechanism. Initially, 6-phosphogluconate binds to the active site of the enzyme. The enzyme then facilitates the transfer of a hydride ion from the substrate to NADP+, forming NADPH. This is followed by the decarboxylation of the substrate, releasing [[carbon dioxide]] and forming ribulose 5-phosphate.
-== Mechanism ==
+==Clinical significance==
-The catalytic mechanism of 6-phosphogluconate dehydrogenase involves the oxidation of the C3 hydroxyl group of 6-phosphogluconate to a ketone, followed by decarboxylation to form ribulose 5-phosphate. The reaction proceeds with the transfer of a hydride ion from the substrate to NADP+, forming NADPH. This reaction is an example of an [[oxidative decarboxylation]], a common type of reaction in metabolic pathways.
+Deficiencies in 6-phosphogluconate dehydrogenase can lead to disruptions in the pentose phosphate pathway, affecting the production of NADPH. This can have downstream effects on cellular processes that rely on NADPH, such as the detoxification of reactive oxygen species. However, such deficiencies are rare compared to other enzyme deficiencies in the pathway, such as [[glucose-6-phosphate dehydrogenase deficiency]].
-== Clinical Significance ==
+==Related pages==
-Deficiencies in 6-phosphogluconate dehydrogenase can lead to disruptions in the pentose phosphate pathway, affecting the production of NADPH and ribose 5-phosphate. This can have downstream effects on [[cellular metabolism]], particularly in cells that rely heavily on NADPH for [[antioxidant defense]] and [[lipid synthesis]].
-== Related Enzymes ==
--Phosphogluconate dehydrogenase is part of a family of dehydrogenases that includes [[glucose-6-phosphate dehydrogenase]] and [[isocitrate dehydrogenase]], which also participate in oxidative decarboxylation reactions and are involved in various metabolic pathways.
-== Related Pages ==
 * [[Pentose phosphate pathway]]
 * [[NADPH]]
 * [[Ribulose 5-phosphate]]
-* [[Oxidative decarboxylation]]
+* [[Glucose-6-phosphate dehydrogenase]]
-== Gallery ==
+==Gallery==
 <gallery>
 File:PDB_1pgq_EBI.jpg|Structure of 6-phosphogluconate dehydrogenase
-File:1pgo.jpg|Another view of the enzyme structure
+File:1pgo.jpg|Crystal structure of the enzyme
 </gallery>
 [[Category:Enzymes]]
 [[Category:Metabolism]]
-[[Category:Dehydrogenases]]
+[[Category:Pentose phosphate pathway]]
+<gallery>
+File:PDB_1pgq_EBI.jpg|Structure of 6-Phosphogluconate dehydrogenase
+File:1pgo.jpg|Another view of 6-Phosphogluconate dehydrogenase
+</gallery>