View source for Phosphoglucomutase

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[[Image:Phosphoglucomutase-1JDY.jpg|thumb|Rabbit muscle phosphoglucomutase, drawn from {{PDB|1JDY}}.]]
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==Overview==
'''Phosphoglucomutase''' ({{EC number|5.4.2.2}}) is an [[enzyme]] that transfers a [[phosphoryl group]] on a glucose [[monomer]] from the 1' to the 6' position in the forward direction or the 6' to the 1' position in the reverse.

More specifically, it facilitates the interconversion of [[glucose 1-phosphate]] and [[glucose 6-phosphate]].

==Pathophysiology==
=== Function in [[Glycogenolysis]]===
After [[glycogen phosphorylase]] has broken off a single [[glucose]] molecule from the greater [[glycogen]] structure, the free [[glucose]] has a [[phosphate]] group on its 1-carbon. This [[glucose-1-phosphate]] [[isomer]] cannot be metabolized easily. The [[enzyme]] phosphoglucomutase phosphorylates the 6-carbon, while subsequently dephosphorylating the 1-carbon. The result is [[glucose-6-phosphate]], which can now theoretically travel down the [[glycolysis]] or [[pentose phosphate pathway]].

=== Function in [[Glycogenesis]]===
Phosphoglucomutase also acts in the opposite fashion when a large concentration of glucose-6-phosphate is present. In this case, it is the 1-carbon that is phosphorylated and the 6-carbon that is dephosphorylated. The resulting glucose-1-phosphate is then changed into UDP-glucose in a number of intermediate steps. If activated by [[insulin]], [[glycogen synthase]] will proceed to clip the glucose from the UDP-glucose complex and on to the glycogen molecule.

===Disease Relevance===
Human muscle contains two phosphoglucomutases with nearly identical catalytic properties, PGM I and PGM II. One or the other of these forms is missing in some humans congenitally.

'''Phosphoglucomutase deficiency''' is an extremely rare condition that does not have a set of well-characterized physiological symptoms. This condition can be detected by an in vitro study of anaerobic glycolysis which reveals a block in the pathway toward lactic acid production after glucose 1-phosphate but before glucose 6-phosphate.

===Genes===
* {{Gene|PGM1}}, {{Gene|PGM2}}, {{Gene|PGM3}}, {{Gene|PGM5}} 

==Related Chapter==
* [[Mutase]]

==External Links==
* {{MeshName|Phosphoglucomutase}}

{{isomerase-stub}}
{{Glycogenolysis}}
{{Mutases}}

==References==
{{Reflist|2}}

[[Category:EC 5.4.2]]