B-GAL Human Recombinant Protein

This gene encodes beta-galactosidase-1, a lysosomal enzyme that hydrolyzes the terminal beta-galactose from ganglioside substrates and other glycoconjugates. Defects in this gene are the cause of GM1-gangliosidosis and Morquio B syndrome. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2008]

GLB1: Cleaves beta-linked terminal galactosyl residues from gangliosides, glycoproteins, and glycosaminoglycans. Defects in GLB1 are the cause of GM1-gangliosidosis type 1 (GM1G1); also known as infantile GM1- gangliosidosis. GM1-gangliosidosis is an autosomal recessive lysosomal storage disease marked by the accumulation of GM1 gangliosides, glycoproteins and keratan sulfate primarily in neurons of the central nervous system. GM1G1 is characterized by onset within the first three months of life, central nervous system degeneration, coarse facial features, hepatosplenomegaly, skeletal dysmorphology reminiscent of Hurler syndrome, and rapidly progressive psychomotor deterioration. Urinary oligosaccharide levels are high. It leads to death usually between the first and second year of life. Defects in GLB1 are the cause of GM1-gangliosidosis type 2 (GM1G2); also known as late infantile/juvenile GM1- gangliosidosis. GM1G2 is characterized by onset between ages 1 and 5. The main symptom is locomotor ataxia, ultimately leading to a state of decerebration with epileptic seizures. Patients do not display the skeletal changes associated with the infantile form, but they nonetheless excrete elevated amounts of beta-linked galactose-terminal oligosaccharides. Inheritance is autosomal recessive. Defects in GLB1 are the cause of GM1-gangliosidosis type 3 (GM1G3); also known as adult or chronic GM1- gangliosidosis. GM1G3 is characterized by a variable phenotype. Patients show mild skeletal abnormalities, dysarthria, gait disturbance, dystonia and visual impairment. Visceromegaly is absent. Intellectual deficit can initially be mild or absent but progresses over time. Inheritance is autosomal recessive. Defects in GLB1 are the cause of mucopolysaccharidosis type 4B (MPS4B); also known as Morquio syndrome B. MPS4B is a form of mucopolysaccharidosis type 4, an autosomal recessive lysosomal storage disease characterized by intracellular accumulation of keratan sulfate and chondroitin-6-sulfate. Key clinical features include short stature, skeletal dysplasia, dental anomalies, and corneal clouding. Intelligence is normal and there is no direct central nervous system involvement, although the skeletal changes may result in neurologic complications. There is variable severity, but patients with the severe phenotype usually do not survive past the second or third decade of life. Belongs to the glycosyl hydrolase 35 family. 3 isoforms of the human protein are produced by alternative splicing.

Protein type: Glycan Metabolism - other glycan degradation; Glycan Metabolism - glycosphingolipid biosynthesis - ganglio series; Glycan Metabolism - glycosaminoglycan degradation; Lipid Metabolism - sphingolipid; EC 3.2.1.23; Carbohydrate Metabolism - galactose; Hydrolase

Chromosomal Location of Human Ortholog: 3p21.33

Cellular Component: Golgi apparatus; lysosomal lumen; perinuclear region of cytoplasm; cytoplasm; vacuole

Molecular Function: protein binding; galactoside binding; beta-galactosidase activity

Biological Process: keratan sulfate metabolic process; sphingolipid metabolic process; dolichol-linked oligosaccharide biosynthetic process; glycosaminoglycan metabolic process; pathogenesis; post-translational protein modification; galactose catabolic process; glycosaminoglycan catabolic process; cellular protein metabolic process; carbohydrate metabolic process; protein amino acid N-linked glycosylation via asparagine; glycosphingolipid metabolic process; cellular carbohydrate metabolic process; keratan sulfate catabolic process

Disease: Gm1-gangliosidosis, Type Iii; Mucopolysaccharidosis Type Ivb; Gm1-gangliosidosis, Type Ii; Gm1-gangliosidosis, Type I