グリコーゲン脱分枝酵素

Recommended name:

Glycogen debranching enzyme

Including the following 2 domains:

4-alpha-glucanotransferase

EC=2.4.1.25
Alternative name(s):
Oligo-1,4-1,4-glucantransferase

Amylo-alpha-1,6-glucosidase

Short name=Amylo-1,6-glucosidase
EC=3.2.1.33

Gene names

Name: AGL
Synonyms: GDE

Function

Multifunctional enzyme acting as 1,4-alpha-D-glucan:1,4-alpha-D-glucan 4-alpha-D-glycosyltransferase and amylo-1,6-glucosidase in glycogen degradation.

Catalytic activity

Transfers a segment of a (1->4)-alpha-D-glucan to a new position in an acceptor, which may be glucose or a (1->4)-alpha-D-glucan.
Hydrolysis of (1->6)-alpha-D-glucosidic branch linkages in glycogen phosphorylase limit dextrin.

Subunit structure

Monomer. Interacts with NHLRC1/malin. Ref.10

Subcellular location

Cytoplasm. Note: Under glycogenolytic conditions localizes to the nucleus. Ref.10

Tissue specificity

Liver, kidney and lymphoblastoid cells express predominantly isoform 1; whereas muscle and heart express not only isoform 1, but also muscle-specific isoform mRNAs (isoforms 2, 3 and 4). Isoforms 5 and 6 are present in both liver and muscle.

Post-translational modification

The N-terminus is blocked.
Ubiquitinated. Ref.10

Involvement in disease

Defects in AGL are the cause of glycogen storage disease type 3 (GSD3) [MIM:232400]; also known as Forbes disease. GSD3 is a metabolic disorder associated with an accumulation of abnormal glycogen with short outer chains. Three GSD3 types are recognized: GSD type 3A patients lack glycogen debrancher enzyme activity in both liver and muscle, while GSD type 3B patients are enzyme-deficient in liver only. In rare cases, selective loss of only 1 of the 2 debranching activities, glucosidase or transferase, results in GSD type 3C or type 3D, respectively. GSD3 is clinically characterized by hepatomegaly, hypoglycemia, short stature, and variable myopathy. Ref.10 Ref.12

Sequence similarities

Belongs to the glycogen debranching enzyme family.

Sequence caution

The sequence BAD92104.1 differs from that shown. Reason: Erroneous initiation.