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

Two different protein activators were isolated simultaneously from human liver for the enzymic hydrolysis of GM1 (Gal beta 1 leads to 3GalNAc beta 1 leads to 4Gal(3 comes from 2 alpha NeuAc)beta 1 leads to 4Glc-Cer) by beta-galactosidase and GM2 (GalNAc beta 1 leads to 4Gal(3 comes from 2 alpha NeuAc)beta 1 leads to 4Glc-Cer) by beta-hexosaminidase A. The hydrolysis of GM1 is stimulated only by the GM1-specific activator which has very little effect on the hydrolysis of GM2. The same is also true for the hydrolysis of GM2. The antiserum raised against GM1 activator did not cross-react with GM2 activator and vice versa. These results suggest the presence of two different activators for the separate hydrolysis of GM1 and GM2. In connection with the enzymic hydrolysis of GM1 and GM2, we found that the hydrolysis of GM2 by human hepatic beta-N-acetylhexosaminidase A was severely inhibited by a buffer of high ionic strength, whereas no such inhibition was observed in the hydrolysis of GM1 by beta-galactosidase.
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PMID:Evidence for the presence of two separate protein activators for the enzymic hydrolysis of GM1 and GM2 gangliosides. 11 63

The gangliosidoses comprise an-ever increasing number of biochemically and phenotypically variant diseases. In most of them an autosomal recessive inherited deficiency of a lysosomal hydrolase results in the fatal accumulation of glucolipids (predominantly in the nervous tissue) and of oligosaccharides. The structure, substrate specificity, immunological properties of and genetic studies on the relevant glycosidases, ganglioside GM1 beta-galactosidase and beta-hexosaminidase isoenzymes, are reviewed in this paper. Contrary to general expectation, only a poor correlation is observed between the severity of the disease and residual activity of the defective enzyme when measured with synthetic or natural substrates in the presence of detergents. For the understanding of variant diseases and for their pre- and postnatal diagnosis, the necessity of studying the substrate specificity of normal and mutated enzymes under conditions similar to the in vivo situation, e.g., with natural substrates in the presence of appropriate activator proteins, is stressed. The possibility that detergents may have adverse affects on the substrate specificity of the enzymes is discussed for the beta-hexosaminidases. The significance of activator proteins for the proper interaction of lipid substrates and water-soluble hydrolases is illustrated by the fatal glycolipid storage resulting from an activator protein deficiency in the AB variant of GM2-gangliosidosis. Recent somatic complementation studies have revealed the existence of a presumably post-translational modification factor necessary for the expression of ganglioside GM1 beta-galactosidase activity. This factor is deficient in a group of variants of GM1-glangliosidosis. Among the possible reasons for the variability of enzyme activity levels in heterozygotes and patients, allelic mutations, formation of hybrid enzymes, and the existence of patients as compound heterozygotes are discussed. All these may result in the production of mutant enzymes with an altered specificity for a variety of natural substrates.
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PMID:Biochemistry and genetics of gangliosidoses. 11 55

A clinical description of an apparently classical case of type 1 GM1 gangliosidosis is presented. The patient was the first-born child of first cousins. She was diagnosed at 6 weeks and died at 6 months. beta-Galactosidase activity was deficient in cultured fibroblasts using [3H]GM1 ganglioside and [3H]ceramide-lactose as substrates. Genetic complementation studies performed after cell fusion between cultured fibroblasts from the patient and from two other type 1, one type 2, and one juvenile GM1 gangliosidosis strain were positive with all strains. Subsequent studies revealed an increased excretion of a sialic acid-containing hexasaccharide in the patient's cells. Parents' fibroblasts contained normal levels of beta-galactosidase. The case emphasizes the variability of the clinical expression in sialidosis and the importance of demonstrating a primary gene defect in establishing a diagnosis of an inborn error or metabolism.
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PMID:Infantile sialidosis: a phenocopy of type 1 GM1 gangliosidosis distinguished by genetic complementation and urinary oligosaccharides. 11

Evidence is presented for the existence of three distinct mammalian glycosphingolipid beta-galactosidase responsible for the hydrolysis of galactosylceramide, lactosylceramide and GM1 gangliside, respectively. Activity toward the (L-3-H)galactose-labeled substrates differed with respect to pH optimum, thermostability, effect of NaCl and inhibition by glycosides and related glycosphinglpids. Comparison of these enzymic acitivites in cultured mouse cell line LMTK- and human beta-galactosiddases could probably be detected in future experiments with somatic cell hybrids (formed by the fusion of these two cell strains by specifically inhibiting activity of mouse origin.
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PMID:Glycosphinoglipid beta-galactosidases of cultured mammalian cells. Characterization of the enzymes from mouse cell line lmtk and human Lesch-Nyhan fibroblasts. 23 34

A simple procedure has been devised to isolate beta-galactosidase from jack bean meal. The final preparation gives one major protein banc in disc gel electrophoresis. The substrate specificity of this enzyme toward some natural oligosaccharides, glycoproteins, and sphingoglycolipids has been examined in detail. Among three isomers of N-acetyllactosamine, Galbeta1leads to4GlcNAc; while Galbeta1leads to3GlcNAc was hydrolyzed very slowly. This property can be used to distinguish the galactose linkage in asialo-GM1 (Galbeta1leads to3GalNAcbeta1leads to4Galbeta1leads to4Glcleads toCer) and that in lacto-N-neotetraosylceramide (Galbeta1leads to4GlcNAcbeta1leads to 3Galbeta1leads to4Glcleads toCer). For hydrolyzing glycolipids, the effect of sodium taurodeoxycholate and sodium taurochenodeoxycholate on the rate of hydrolysis was carefully examined. This enzyme hydrolyzes lactosylceramide and asialo-GM1 faster than GM1. These results suggest that in addition to the type and linkage of the penultimate sugar unit, the sugar unit at the distal position of the saccharide chain also affects the hydrolysis rate. It also readily liberates 80% D-galactosyl units from asialo alpha1-acid glycoprotein. Escherichia coli beta-galactosidase on the other hand cannot hydrolyze asialo-alpha1-acid glycoprotein, lactosylceramide, GM1, asialo-GM1, and lacto-N-neotetraosylceramide. The molecular weight of this enzyme is about 75,000 and the isoelectric point is pH 8.0. With p-nitrophenyl beta-D-galactopyranoside as substrate, optimal activity occurs at pH 2.8 with glycine-HCl buffer and at pH 3.5 with citrate-phosphate buffer. With lactose as substrate, the pH optimum in these two buffers are 2.8 and 4.0, respectively. Km values for p-nitrophenyl beta-D-galactopyranoside, o-nitrophenyl beta-D-galactopyranoside and lactose are 0.51 mM, 0.63 mM, and 12.23 mM, respectively. Many inhibitors for this enzyme including inorganic ions, monosaccharides, and glycosides are investigated. In contrast to E. coli beta-galactosidase, jack bean beta-galactosidase is not inhibited by p-aminophenyl thio-beta-D-galactopyranoside.
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PMID:Isolation and characterization of jack bean beta-galactosidase. 23 49

An adult patient with macular cherry-red spots, a gargoyle-like physical appearance, cerebellar ataxia, myoclonus, convulsive seizures, and pyramidal tract signs showed a profound deficiency of beta-galactosidase in liver and brain. Thrombocytopathy of undetermined etiology was evident since childhood, and the patient died of intracranial bleeding at age 22. Cerebral ganglioside pattern was normal. Hepatic mucopolysaccharides were not increased. GM1-gangliosidosis and mucopolysaccharidosis were ruled out by those analytical data. However, a large amount of amylopectin-like polysaccharide was found to be accumulated in liver. Hepatocyte contained numerous inclusion bodies with granulofibrillary structure similar to Lafora bodies, corpora amylacea, and inclusion bodies in glycogenosis type IV. This case seems to represent a new inborn metabolic disease closely related to GM1-gangliosidosis and mucopolysaccharidosis. The primary metabolic defect is not known at present.
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PMID:Macular cherry-red spots and beta-galactosidase deficiency in an adult. An autopsy case with progressive cerebellar ataxia, myoclonus, thrombocytopathy, and accumulation of polysaccharide in liver. 40 3

beta-Galactosidase activities were studied in livers and leukocytes of mucopolysaccharidoses and mucolipidoses (I-cell disease and adult "beta-galactosidase deficiency" with macular cherry-red spots). Marked deficiency of hepatic 4-methylumbelliferyl (4MU) and GM1 beta-galactosidases was demonstrated in these diseases. Leukocyte GM1 beta-galactosidase was also deficient in mucolipidoses. The parents of the patients with I-cell disease and "beta-galactosidase deficiency" had normal beta-galactosidase activity in plasma and leukocytes, compared to the low enzyme activity in heterozygous carriers of GM1-gangliosidosis. The cause of this enzyme deficiency in these diseases is not clear at present. It seems to be affected seondarily by exgenous factors such as unknown stored materials in the cells. Mucopolysaccharides were not increased in the livers of two cases of I-cell disease and a case of "beta-galactosidase deficiency".
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PMID:beta-Galactosidase in mucopolysaccharidoses and mucolipidoses. Deficiency of GM1 beta-galactosidase in liver and leukocytes. 40 36

Six juvenile and adult patients with progressive neurological diseases and beta-galactosidase deficiency were reported. Any diseases known to date were denied. These cases together with ten case reports in the literature were reviewed and were classified into three groups from clinical and biochemical points. Group 1 patients were characterized by progressive ataxia and myoclonus with gargoyl changes and macular cherry-red spots. In this syndrome beta-galactosidase activity seems to be secondarily affected by other biochemical defects. A group 2 patient showed similar neurological manifestations without gargoyle changes or macular cherry-red spots. Patients with these clinical features not associated with beta-galactosidase deficiency have also been described in the literature. Group 3 patients had progressive pyramidal and extrapyramidal disease without gargoyl changes or macular cherry-red spots. These cases may represent juvenile and adult type GM1-gangliosidosis. Accumulation of GM1 has not yet been demonstrated.
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PMID:beta-Galactosidase deficiency in juvenile and adult patients. Report of six Japanese cases and review of literature. 40 31

Two cases of Gangliosidosis GM1 are presented. They are a child who showed psychomotor backward and generalized osteoporosis, died at 16 months, and a girl studied because of psychomotor backward when she was less than a year. This girl showed radiological vertebrae alterations similar to mucopolysaccharidosis and died when she was 7 years old. The enzymatic determinations in serum and cultured fibroblasts showed beta-galactosidase deficiency in both cases. Important storage of cerebral gangliosides with increase of the percentage of GM1 was also found in both cases. Histological alterations were found in some other organs besides the brain.
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PMID:[Gangliosidosis GM1. Clinical, radiologic, biochemical and histological studies in two cases (author's transl)]. 40 24

The apparent low level of synthetic substrate beta-D-galactosidase activity in liver from patients with the Hurler-Hunter syndrome is caused by the inhibitory effect of accumulated glycosaminoglycans. We have demonstrated complete inhibition of GM1 ganglioside beta-galactosidase activity in vitro by both heparan sulfate and dermatan sulfate, but the effect on lactosylceramide and galactosylceramide hydrolysis was less marked. In contrast, lysosomal neuraminidase activity in vitro was enhanced by the addition of glycosaminoglycans. These observations are discussed in relationship to the observed storage pattern of glycosphingolipids in liver from patients with mucopolysaccharidoses.
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PMID:The effect of glycosaminoglycans on the in vitro activity of human skin fibroblast glycosphingolipid beta-galactosidases and neuraminidases. 40 73


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