Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
UDP-alpha-D-glucose + glycogenin | Homo sapiens | - |
UDP + alpha-D-glucosylglycogenin | - |
? | |
UDP-alpha-D-glucose + glycogenin | Mus musculus | - |
UDP + alpha-D-glucosylglycogenin | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Homo sapiens | O15488 | - |
- |
Homo sapiens | P46976 | - |
- |
Mus musculus | Q9R062 | - |
- |
Posttranslational Modification | Comment | Organism |
---|---|---|
glycoprotein | the enzyme performs autoglucosylation | Homo sapiens |
glycoprotein | the enzyme performs autoglucosylation | Mus musculus |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
heart | - |
Homo sapiens | - |
heart | - |
Mus musculus | - |
liver | isozyme glycogenin-2 | Homo sapiens | - |
additional information | glycogenin-1 is ubiquitously expressed and the only isoform in human skeletal muscle | Homo sapiens | - |
skeletal muscle | - |
Mus musculus | - |
skeletal muscle | glycogenin-1 is ubiquitously expressed and the only isoform in human skeletal muscle | Homo sapiens | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
additional information | the enzyme performs autoglucosylation | Homo sapiens | ? | - |
- |
|
additional information | the enzyme performs autoglucosylation | Mus musculus | ? | - |
- |
|
UDP-alpha-D-glucose + glycogenin | - |
Homo sapiens | UDP + alpha-D-glucosylglycogenin | - |
? | |
UDP-alpha-D-glucose + glycogenin | - |
Mus musculus | UDP + alpha-D-glucosylglycogenin | - |
? |
Synonyms | Comment | Organism |
---|---|---|
glycogenin | - |
Homo sapiens |
glycogenin | - |
Mus musculus |
glycogenin-1 | - |
Homo sapiens |
glycogenin-1 | - |
Mus musculus |
glycogenin-2 | - |
Homo sapiens |
GYG1 | - |
Homo sapiens |
GYG1 | - |
Mus musculus |
GYG2 | - |
Homo sapiens |
General Information | Comment | Organism |
---|---|---|
evolution | unlike mice, humans and other primates have a second variant of glycogenin called glycogenin-2, which is mainly expressed in the liver | Homo sapiens |
evolution | unlike mice, humans and other primates have a second variant of glycogenin called glycogenin-2, which is mainly expressed in the liver | Mus musculus |
malfunction | complete lack of glycogenin-1 is usually associated with late onset muscle weakness, indicating that lack of glycogenin-1 has no major impact on muscle energy metabolism. The muscle weakness that appears later in life is associated with muscle fiber degeneration, replacement of muscle tissue by fat and fibrous connective tissue explains the weakness. Several recessive pathogenic mutations have been identified in the glycogenin-1 gene, GYG1. Complete absence of glycogenin-1 protein secondary tobi-allelic truncating mutations in GYG1 causes a rare muscle disease that is characterized by accumulation of glycogen. This glycogen is, in addition to lack of a glycogenin-1 core, abnormal with regard to its ultrastructure. Many glycogen particles show uneven size and irregular shape, and some of the storage material has a fibrillar structure. A more severe heart disease associated with missense GYG1 mutations has been described in several individuals. Muscle glycogen depletion caused by truncating mutations in GYS1, which encodes the ubiquitously expressed glycogen synthase, does not result in a compensatory upregulation of the liver glycogen synthase isoform. In patients with total lack of glycogen due to muscle glycogen synthase deficiency, glycogenin-1 is present in similar quantities as in normal individuals | Homo sapiens |
malfunction | glycogenin inactivation in mice results in an increased amount of glycogen and not glycogen depletion. Overproduction of glycogen secondary to glycogenin deficiency is associated with altered metabolism, affecting mainly oxidative muscle fibers and causing impaired endurance. Glycogenin KO mice show accumulation of glycogen instead of glycogen depletion, and no protein that functions as a substitute for glycogenin has been identified. The lack of glycogenin is associated with reduced endurance and a metabolic shift toward glycolytic metabolism in the otherwise fatigue-resistant oxidative muscle fibers. The results from the mouse glycogenin KO experiments support the concept that glycogenin is not mandatory for glycogen synthesis, although deficiency causes metabolic impairment with reduced endurance | Mus musculus |
malfunction | muscle glycogen depletion caused by truncating mutations in GYS1, which encodes the ubiquitously expressed glycogen synthase, does not result in a compensatory upregulation of the liver glycogen synthase isoform | Homo sapiens |
physiological function | glycogenin is a core protein in glycogen particles and functions as a glycosyl transferase with the ability to autoglucosylate | Homo sapiens |
physiological function | glycogenin is a core protein in glycogen particles and functions as a glycosyl transferase with the ability to autoglucosylate. A primer protein is dispensable for glycogen synthesis. Glycogenin appears to have a role in the regulation of glycogen content | Mus musculus |