Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The molecular genetics of GM1 beta-galactosidase is reviewed. This enzyme exists in two forms, A and B. Form A is monomeric with a molecular weight of 72,000 and appears to be coded by a single autosomal locus. Form B is polymeric and cross-reacts with anti-A antibodies; it is coded wholly or in part by the same locus that codes for A. The simultaneous loss of A and B in GM1 gangliosidosis is explained. None of the other beta-galactosidases, including neutral beta-galactosidase, ceramide lactoside beta-galactosidase or cerebroside beta-galactosidase cross-react with anti-A antibodies, demonstrating that they are coded by loci separate from A. GM1 beta-galactosidase A is heterocatalytic, cleaving beta-D-galactose from ganglioside GM1, lactose, N-acetyllactosamine, and galactose-containing glycoproteins such as asialofetuin, red cell stromal glycoproteins and keratan sulfate. The pleotropic effects of a single mutation affecting the locus for beta-galactosidase A can be explained by a one gene:one polypeptide:many substrates model. Phenotypic variability among beta-galactosidase A mutants may result from better residual activity of the mutant enzyme for one substrate than for another. Patients with normal intelligence and severe bony deformities, who are homozygous for a mutation affecting the enzyme, illustrate this point. Thus far all human mutants for GM1 beta-galactosidase studied are structural mutants, synthesizing nearly normal quantities of mutant enzyme; one is a proven Km mutant, the others are very likely so.
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PMID:Molecular genetics of GM1 beta-galactosidase. 81 20

An activator stimulating the enzymic hydrolysis of sphingoglycolipids has been purified from human liver. The purity of the activator, as examined by disc gel electrophoresis, showed one major band stained with both amido black and periodate-Schiff reagent. Chemical analyses identify the activator as a glycoprotein. The physical properties of the activator are: heat-stable, nondialyzable; molecular weight, about 21,000; isoelectric point (pI), 4.1. The purified activator stimulates the hydrolysis of GM1 by beta-galactosidase, GM2 by beta-hexosaminidase, as well as ceramide trihexoside by alpha-galactosidase A or B. The hydrolysis by glycosidases depends upon the amount of activator added. An antibody against the activator was developed from rabbits. The specificity of the antibody to the activator has been established. The antibody was used to make the affinity column for isolation of the activator. It was also used to develop a sensitive immunodiffusion method to detect the activator.
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PMID:An activator stimulating the enzymic hydrolysis of sphingoglycolipids. 81 23

Biochemical data are presented of a 29-year-old male, who shows progressive psychomotor retardation and a beta-galactosidase deficiency in leucocytes and cultured skin fibroblasts. Somatic cell hybridization studies show that this variant of GM1-gangliosidosis is based on a different gene mutation than is present in types 1 and 2. No complementation is observed in fusion experiments with cells from type 3 variant.
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PMID:beta-Galactosidase deficiency in an adult: a biochemical and somatic cell genetic study on a variant of GM1-gangliosidosis. 81 80

A 14-year-old girl with a unique type of progressive spondyloepiphyseal dysplasia, corneal clouding, and no evidence of neurological abnormality, was found to have a remarkable deficiency of acid beta-galactosidase activity in cultured skin fibroblasts and in leucocyte preparations. In fibroblasts, ganglioside GM1 beta-galactosidase activity averaged 7% of the normal mean while asialofetuin beta-galactosidase and 4-methylumbe lifery-beta-galactosidase averaged 1.4% and 3.5%, respectively. Activities for all three substrates in leucocytes from both her parents were close to 50% of the normal mean indicating that the patient is homozygous for a mutation (or mutations) affecting GM1 beta-galactosidase.
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PMID:Spondyloepiphyseal dysplasia, corneal clouding, normal intelligence and acid beta-galactosidase deficiency. 81 53

A case of GM1-gangliosidosis with high activity of hepatic neutral beta-galactosidase is reported. GM1-beta-galactosidase was deficient. Ganglioside GM1 was accumulated in the liver of this patient. Clinically this Japanese girl started convulsive seizures at 5 months of age, had hepatomegaly, and macular cherry-red spots, but lacked gargoylelike clinical characteristics. Correlation of clinical and biochemical data is discussed.
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PMID:Gmi-gangliosidosis. A variant with high activity of hepatic neutral beta-galactosidase. 81 72

Clinical, histological, ultrastructural and biochemical studies have been performed in a living 20-month-old infant with GM1-gangliosidosis type 2. Rectum, brain and liver biopsies were done. The histological and ultrastructural examination revealed the presence of cytoplasmic membranous bodies in the nervous system and a vacuolisation of the visceral parenchymatous cells, particularly histiocytes. The diagnosis was established by the finding of a generalized beta-galactosidase deficiency and an accumulation of GM1-ganglioside in brain. In leukocytes, the activity of p-nitrophenyl-beta-galactosidase was below 5%, and that of GM1-ganglioside beta-galactosidase below 1% of values obtained in controls. In cerebral tissue, GM1 ganglioside constituted 80% of total gangliosides; its concentration was 15 times that in age-matched controls. No accumulation of GM1 could be evidence in liver. Enzymatic examination of leukocytes obtained from the consanguineous parents revealed heterozygote values.
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PMID:[Clinical, ultrastructural and biochemical study of a case of GM1 type 2 gangliosidosis]. 82 51

A biochemical analysis was carried out on three cases of GM1-gangliosidosis which showed different clinical manifestations. These cases were classified in a previous study as Type 1, Type 2 (2B) and Type 2 (2A), an intermediate type between classical Type 1 and Type 2 (2B), by the determination of the chromatographic profile of the liver beta-galactosidase activities. Gangliosides, neutral glycolipids; phospholipids and glycopeptides were analyzed in the brain and the liver of these cases. The concentration of total ganglioside was increased in the brain in all cases. The elevation was due to an increase of GM1-ganglioside, which accounted for 63% or more of the total ganglioside, while in the control brain about 20% of the total ganglioside was GM1-ganglioside. In type 2A, increases of GM1-ganglioside and and asialo-GM1 in the liver were more prominent than those in the liver of Type 2B. The non-dialyzable glycopeptides were analyzed only in Type 2A. In the liver of Type 2A, the hexosamine and hexose contents of the non-dialyzable glycopeptides were about 10 times and 5 times higher than those of the control. These biochemical analyses revealed that Type 2A had intermediate characteristics between two Types. In this classification of the three Types, biochemical data were well correlated with clinical features.
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PMID:Three cases of GM1-gangliosidosis. 82 79

Corneal clouding is added to the list of clinical and chemical abnormalities which occur both in GM1-generalized gangliosidosis and in Hurler's syndrome (and some other mucopolysaccharidoses). The parents of our patient were first cousin Yemeni and had partial beta-galactosidase deficiency in their leucocytes and cultured fibroblasts.
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PMID:Corneal clouding in GM1-generalized gangliosidosis. 82 60

A 9-month-old dog with a history of progressive motor dysfunction was shown to have a deficiency in brain beta-galactosidase activity. The canine disease, like that of children with GM1 gangliosidosis, is characterized by accumulation of GM1 ganglioside in the brain, liver, and spleen, and membranous cytoplasmic bodies in neurons. The dog's pedigree suggests an autosomal recessive pattern of inheritance.
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PMID:Neuronal-visceral GM1 gangliosidosis in a dog with beta-galactosidase deficiency. 82 30

The brain and liver from a 7-year-old Japanese girl with juvenile amaurotic idiocy were examined neuropathologically and biochemically. Visceromegaly and skeletal abnormalities were absent. Nerve cells in the central nervous system were swollen and contained fine fat granules. Electronmicroscopically, there were large numbers of irregular bodies in the perikarya and these corresponded to the curvilinear and membranous cytoplasmic bodies. Lipid analysis of the brain revealed that GM1 ganglioside was increased in the parietal and occipital areas, while the frontal lobe showed a normal ganglioside pattern. N-Acetyl neuraminic acid (NANA) content in all areas was not elevated. Determinations of beta-galactosidase activity were within normal ranges. The liver had no accumulation of GM1 ganglioside and showed a normal beta-galactosidase activity. These unusual findings in GM1 gangliosidosis were discussed.
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PMID:Atypical GM1 ganglioside accumulation in a case of juvenile amaurotic idiocy. 88 52


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