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 activity of neuraminidase in liver and brain from I-cell disease (Mucolipidosis II) was investigated. Neuraminidase activities using two substrates [alpha-L-N-acetylneuraminosyl(2 leads to 3)lactose and alpha-L-N-acetylneuraminosyl(2 leads to 6)lactose] were reduced in the supernatant and sedimentable fractions obtained in isotonic KCl. The activity of beta-D-galactosidase was also reduced in the liver; on the other hand, both neuraminidase fractions were normal, although beta-galactosidase activities were markedly reduced. In view of these results, it is suggested that the defect of neuraminidase is not directly responsible for the primary etiology of I-cell disease.
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PMID:Neuraminidase activity in liver and brain from patients with I-cell disease. 11 36

Neuraminidase was assayed in the frozen autopsy tissues from three patients with I-cell disease and an adult patient with cherry-red spots, myoclonus, cerebellar ataxia and beta-galactosidase deficiency. Both diseases showed normal neuraminidase activity toward neuramine lactose and fetuin in cerebral gray matter, liver and kidney. These results suggest that the neuraminidase deficiency is limited only to some tissues and that this biochemical abnormality is not caused by a primary genetic mutation in these diseases.
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PMID:Neuraminidase in mucolipidoses: normal activity in frozen autopsy tissues from three patients with I-cell disease and adult beta-galactosidase deficiency. 11 81

Two adult siblings with progressive pyramidal and extrapyramidal lesions, and generalized muscle atrophy had a profound deficiency of beta-galactosidase in all the cells and body fluids examined. Neuraminidase activity was normal in fibroblasts. The fused fibroblasts of infantile GMl-gangliosidosis and each of these adult patients had beta-galactosidase activity as expected for the average value in a mixture of equal numbers of parental cells. However, there was a remarkable increase in the activity of beta-galactosidase when the cells from each of these cases were fused with those from the beta-galactosidase-deficient adult with cherry-red spots, cerebellar ataxia, myoclonus and neuraminidase deficiency in fibroblasts. It was concluded that the two siblings represent a new genetic variant (adult type) of GMl-gangliosidosis.
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PMID:Adult type GMl-gangliosidosis: a complementation study on somatic cell hybrids. 12 69

The effect of sugars on 125I-thyroid-stimulating hormone binding to beef thyroid membranes was studied to determine their role in thyroid-stimulating hormone (TSH) binding. At 0.1 M concentration, N-acetylneuraminic acid produced a 3- to 7-fold increase in TSH binding, was the only sugar to enhance TSH binding, and did so whether binding was determined in the cyclase medium or under conditions of optimum binding. The enhanced TSH binding remained after the membranes were removed from the high NeuAc concentration and an effect was observed at concentrations of 10 mM NeuAc. NeuAc did not alter the kinetics of TSH binding but the pH optimum for TSH binding shifted from pH 5.5 to 7.5 in the presence of NeuAc. Incubation of the membranes with increasing concentrations of NeuAc resulted in increased sialic acid content of the membranes. The NeuAc concentration curve of membrane sialic acid and TSH binding were roughly parallel. The capacity of the low affinity site increased from 0.74 to 2.5 nmol/mg of protein in the presence of NeuAc. The apparent affinity (0.88 X 10(6) M-1) of this site was unaffected by NeuAc. With the high affinity site, NeuAc increased both the apparent affinity and capacity from 2.2 X 10(8)M-1 to 5.5 X 10(8) M-1 and 1.6 to 3.1 pmol/mg of protein, respectively. Neuraminidase or neuraminidase plus beta-galactosidase incubation of the membranes removed approximately 60% of the sialic acid from the membranes within 15 to 30 min but did not affect TSH binding. Large quantities of sialic acid were detected in the soluble fractions during isolation of the membranes, 4 to 5% of which was ultrafilterable and not associated with high molecular weight proteins. It is concluded that among the sugars tested, NeuAc exhibits an unique effect on TSH binding that may have physiological significance. The inability to alter TSH binding by enzymatic removal of endogenous sialic acid suggests that either NeuAc resistant to hydrolysis is sufficient to maintain TSH binding or that NeuAc important in TSH binding is removed during membrane preparation but is replaced by incubation with exogenous NeuAc.
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PMID:Thyroid-stimulating hormone binding to beef thyroid membranes. Role of N-acetylneuraminic acid. 18 21

The nature of the binding of C. parvum organisms to the surface of glass-adherent mouse peritoneal exudate cells in vitro was studied using pretreatment of the cells with various enzymes and periodate. Trypsin, pronase, beta-galactosidase, phospholipases A, C and D and periodate all caused a decrease in binding to 40-60% of untreated control. Neuraminidase led to a 30% increase in binding. The binding ability returned to normal after 1 h at 37 degrees in culture medium following exposure to all the enzymes apart from pronase, which apparently could not be removed effectively by washing. The presence of EDTA in the medium inhibited recovery from treatment with trypsin and beta-galactosidase; return to normal after exposure to phospholipases A, C and D was slightly affected, whereas recovery from treatment with neuraminidase was unaffected. Cells that had been exposed to periodate did not regain normal binding ability after 1 h in tissue culture medium but the effect could be reversed chemically by treatment with borohydride. The role of different plasma membrane components in non-specific cellular recognition is discussed.
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PMID:Binding of microorganisms to the macrophage plasma membrane; effects of enzymes and periodate. 20 34

Several classes of proteolytic enzymes were used to gain an insight into the biochemical composition of the antiotensin II (ATII) receptor prepared from bovine adrenal cortices. Exposure of the receptor fractions to trypsin reduced their capacity to bind [3H]ATII. Phospholipases A2 and C similarly inhibited the [3H]ATII binding process, while phospholipase D had no effect. Binding was stimulated following addition of phosphatidylcholine but inhibited by lysophosphatidylcholine. Neuraminidase had no influence on [3H]ATII affinity for binding, while beta-galactosidase reduced binding of the radioligand. Concanavalin A did not displace [3H]ATII bound to receptor fractions. Very little aminopeptidase activity was detected in the receptor fraction, relative to the homogenate. The data suggest that the ATII recognition sites contain protein moieties, while phospholipids may play an essential role in ATII binding. Galactose units may form a part of the ATII receptor not directly associated with the binding site. The peptidase studies indicate that ATII probably cannot be hydrolyzed to its des-Asp1 metabolite at or near the site of binding.
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PMID:Enzymatic modifications of bovine adrenocortical angiotensin II receptors. 22 26

Neuraminidase (EC 3.2.1.18) beta-galactosidase (EC 3.2.1.23) and beta-N-acetylglucosaminidase (EC 3.2.1.30) were studied in normal and regenerating rat liver. All these glycosidases were shown to be predominantly localized in lysosome rich fraction. The activity of lysosomal neuraminidase in regenerating rat liver increased 24 hours after partial hepatectomy, whereas those of beta-galactosidase and beta-N-acetylglucosaminidase decreased. The presence of inhibitor of neurominidase in regenerating liver homogenate was shown. Actinomycin D and cycloheximide were shown to have no significant effect on lysosomal neuraminidase in regenerating rat liver.
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PMID:[Lysosomal neuraminidase, beta-galactosidase and beta-N-acetylglucosaminidase of regenerating liver tissue]. 86 11

The 18 kDa and 32 kDa lectin binding proteins of Chlamydia trachomatis were characterized as glycoproteins by treatments with glycosidases. The proteins of the serovar L2 whole cell lysate were separated by SDS-PAGE and transferred to nitrocellulose paper. After treatment with an enzyme, the proteins were reacted with a biotinylated lectin. Each of the endoglycosidases tested affected the binding of the lectin to the protein. PNGase F inhibited the binding of Dolichos biflorus agglutinin (DBA), soybean agglutinin (SBA), and Ulex europaeus agglutinin I (UEAI) to both the 18 kDa and 32 kDa proteins. Endoglycosidase F and H inhibited the binding of these lectins to the 32 kDa protein completely and to the 18 kDa protein partially. In the exoglycosidase treatments, alpha-L-fucosidase prevented binding of only UEAI to the two proteins while beta-galactosidase inhibited the binding of SBA. Mannosidase abolished the binding of all the lectins tested. Neuraminidase had no effect. The proteins isolated by electroelution from the excised gels after SDS-PAGE were digested with an endoglycosidase. PNGase F-treated proteins showed a lower molecular weight mobility in which the lectin binding ability was destroyed. Endo-alpha-N-acetylgalactosaminidase had no effect. The polysaccharide stain of isolated proteins with p-phenylenediamine showed a positive reaction. Radiolabeling with [3H]glucosamine did not reveal the 18 kDa and 32 kDa proteins in autoradiography but [3H]galactose did.
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PMID:The characterization of lectin-binding proteins of Chlamydia trachomatis as glycoproteins. 172 47

A simple procedure for purification of lysosomal beta-galactosidase from rat liver was developed. The association state of the purified enzyme has been found to depend on pH and ionic strength. Under acidic conditions and at high ionic strength, the enzyme is aggregated into a high molecular weight complex having a molecular weight of about 700,000. Increasing pH and lowering the ionic strength favour the disaggregation of the complex to an enzyme species whose molecular weight is 160,000. These two enzyme forms differ markedly in their hydrophobicity, but no significant differences in kinetic properties have been found. Galactose and galactose-1-amine were competitive inhibitors of beta-galactosidase. Neuraminidase is associated with the multimeric form of beta-galactosidase, whereas the low molecular weight form did not show any neuraminidase activity. The stability of neuraminidase has been found increase in the presence of magnesium ions.
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PMID:Lysosomal beta-galactosidase from rat liver: purification, molecular forms and association with neuraminidase. 212 33

Using a panel of 143 strains classified according to a novel taxonomic system for oral viridans-type streptococci, we reexamined the ability of oral streptococci to attack human immunoglobulin A1 (IgA1) molecules with IgA1 protease or glycosidases. IgA1 protease production was an exclusive property of all strains belonging to Streptococcus sanguis and Streptococcus oralis (previously S. mitior) and of some strains of Streptococcus mitis biovar 1. These are all dominant initiators of dental plaque formation. Degradation of the carbohydrate moiety of IgA1 molecules accompanied IgA1 protease activity in S. oralis and protease-producing strains of S. mitis biovar 1. Neuraminidase and beta-galactosidase were identified as extracellular enzymes in organisms of these taxa. By examination with enzyme-neutralizing antisera, four distinct IgA1 proteases were detected in S. sanguis biovars 1 to 3, S. sanguis biovar 4, S. oralis, and strains of S. mitis, respectively. The cleavage of IgA1 molecules by streptococcal IgA proteases was found to be influenced by their state of glycosylation. Treatment of IgA1 with bacterial (including streptococcal) neuraminidase increased susceptibility to protease, suggesting a cooperative activity of streptococcal IgA1 protease and neuraminidase. In contrast, a decrease in susceptibility was observed after extensive deglycosylation of the hinge region with endo-alpha-N acetylgalactosaminidase. The effector functions of IgA antibodies depend on the carbohydrate-containing Fc portion. Hence, the observation that oral streptococci may cleave not only the alpha 1 chains but also the carbohydrate moiety of IgA1 molecules suggests that the ability to evade secretory immune mechanisms may contribute to the successful establishment of these bacteria in the oral cavity.
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PMID:Molecular aspects of immunoglobulin A1 degradation by oral streptococci. 218 37


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