GBA-gene

The GBA gene (GBA is the acronym for glucosylceramidase beta) is located on chromosome 1q22 and encodes a lysosomal membrane protein (glucosylceramidase beta), an enzyme that cleaves the beta-glucosidic bond of glucocerebroside, an intermediate in glycolipid metabolism. Glucosylceramidase beta (also called glucocerebrosidase) is active in lysosomes, small cell organelles that function as recycling centers. Lysosomes use proteolytic enzymes to break down toxic substances, digest bacteria that enter the cell, and recycle other "cellular waste." Because of these functions, the enzymes in the lysosome are also called "housekeeping enzymes".

Diseases associated with mutations in the GBA gene (>300 mutations are known) are Gaucher disease, type I and Gaucher disease, type II . Gaucher disease is a lysosomal storage disease characterized by accumulation of glucocerebrosides in cells. A related pseudogene is located approximately 12 kb downstream of this gene on chromosome1.

Glucosylceramidase beta is one such "housekeeping enzyme" that enzymatically cleaves glucosylceramide into a sugar (glucose) and a simpler fat molecule (ceramide). Glucosylceramide is a component of the membrane that surrounds cells. Thus, the enzyme plays a central role in the degradation of complex lipids and the turnover of cell membranes. Glucosylceramidase beta also plays a role in cholesterol metabolism. Here, the enzyme can either catalyze the glucosylation of cholesterol, through a transglucosylation reaction that transfers glucose from glucosylceramide to cholesterol. Finally, it can also hydrolyze cholesteryl-beta-D-glucoside to produce D-glucose and cholesterol

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