Accepted Name |
glycogenin glucosyltransferase
|
Alternative Name(s) |
glycogenin |
priming glucosyltransferase |
Reaction catalysed |
- L-tyrosyl-[glycogenin] + UDP-alpha-D-glucose = alpha-D-glucosyl-L-tyrosyl-[glycogenin] + UDP + H(+)
- [1,4-alpha-D-glucosyl](n)-L-tyrosyl-[glycogenin] + UDP-alpha-D-glucose = [1,4-alpha-D-glucosyl](n+1)-L-tyrosyl-[glycogenin] + UDP + H(+)
|
Comment(s) |
- The first reaction of this enzyme is to catalyze its own
glucosylation, normally at a specific Tyr of the protein if this
group is free; when the Tyr is replaced by Thr or Phe, the enzyme's
self-glucosylation activity is lost but its intermolecular
transglucosylation ability remains.
- It continues to glucosylate an existing glucosyl group until a length
of about 5-13 residues has been formed.
- Further lengthening of the glycogen chain is then carried out by
EC 2.4.1.11.
- Not highly specific for the donor, using UDP-xylose in addition to
UDP-glucose (although not glucosylating or xylosylating a xylosyl
group so added).
- It can also use CDP-glucose and TDP-glucose, but not ADP-glucose or
GDP-glucose.
- Similarly it is not highly specific for the acceptor, using water
(i.e. hydrolyzing UDP-glucose) among others.
- Various forms of the enzyme exist, and different forms predominate in
different organs.
- Thus primate liver contains glycogenin-2, of molecular mass 66 kDa,
whereas the more widespread form is glycogenin-1, with a molecular
mass of 38 kDa.
- Formerly EC 2.4.1.112.
|
Cross-references |
BRENDA | 2.4.1.186 |
EC2PDB | 2.4.1.186 |
ExplorEnz | 2.4.1.186 |
PRIAM enzyme-specific profiles | 2.4.1.186 |
KEGG Ligand Database for Enzyme Nomenclature | 2.4.1.186 |
IUBMB Enzyme Nomenclature | 2.4.1.186 |
IntEnz | 2.4.1.186 |
MEDLINE | Find literature relating to 2.4.1.186 |
MetaCyc | 2.4.1.186 |
Rhea expert-curated reactions | 2.4.1.186 |
UniProtKB/Swiss-Prot |
A7A018, GLG1_YEAS7 | P36143, GLG1_YEAST | A6ZQJ2, GLG2_YEAS7 |
P47011, GLG2_YEAST | J9VPM2, GLG_CRYNH | C4R941, GLG_KOMPG |
V5ILS6, GLG_NEUCR | O15488, GLYG2_HUMAN | P46976, GLYG_HUMAN |
Q9R062, GLYG_MOUSE | P13280, GLYG_RABIT | O08730, GLYG_RAT |
H2KYQ5, GYG1_CAEEL |
|
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