Phosphoglucomutase

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phosphoglucomutase 1
Identifiers
Symbol(s)	PGM1
Entrez	5236
OMIM	171900
RefSeq	NM_002633
UniProt	P36871
Other data
EC number	5.4.2.2
Locus	Chr. 1 p22.1

phosphoglucomutase 2
Identifiers
Symbol(s)	PGM2
Entrez	55276
OMIM	172000
RefSeq	NM_018290
UniProt	Q96G03
Other data
EC number	5.4.2.2
Locus	Chr. 4 p14-q12

phosphoglucomutase 3
Identifiers
Symbol(s)	PGM3
Entrez	5238
OMIM	172100
RefSeq	NM_015599
UniProt	O95394
Other data
EC number	5.4.2.2
Locus	Chr. 6 q14.1-q15

phosphoglucomutase 5
Identifiers
Symbol(s)	PGM5
Entrez	5239
OMIM	600981
RefSeq	NM_021965
UniProt	Q15124
Other data
Locus	Chr. 9 q13

Phosphoglucomutase (EC 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 dirction or the 6' to the 1' position in the reverse.

[edit] 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.

[edit] 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.