GBE1

1,4-alpha-glucan-branching enzyme, also known as brancher enzyme or glycogen-branching enzyme is an is_associated_with::enzyme that in humans is encoded by the GBE1 is_associated_with::gene.

Function
GBE1 is a is_associated_with::glycogen branching enzyme that catalyzes the transfer of alpha-1,4-linked is_associated_with::glucosyl units from the outer end of a glycogen chain to an alpha-1,6 position on the same or a neighboring glycogen chain. Branching of the chains is essential to increase the solubility of the glycogen molecule and, consequently, in reducing the is_associated_with::osmotic pressure within cells. Highest level of this enzyme are found in liver and muscle.

Clinical significance
Mutations in this gene are associated with glycogen storage disease IV (also known as is_associated_with::Andersen's disease).

Model organisms
is_associated_with::Model organisms have been used in the study of GBE1 function. A conditional is_associated_with::knockout mouse line, called Gbe1tm1a(KOMP)Wtsi was generated as part of the is_associated_with::International Knockout Mouse Consortium program — a high-throughput mutagenesis project to generate and distribute animal models of disease to interested scientists.

Male and female animals underwent a standardized is_associated_with::phenotypic screen to determine the effects of deletion. Twenty six tests were carried out on is_associated_with::mutant mice and two significant abnormalities were observed. No is_associated_with::homozygous is_associated_with::mutant embryos were identified during gestation, and therefore none survived until is_associated_with::weaning. The remaining tests were carried out on is_associated_with::heterozygous mutant adult mice; no additional significant abnormalities were observed in these animals.