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 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

Effect of different concentration of non-ionic detergents (Triton X-100, Triton X-305, BRIJ-35 and Triton WR-1339) on total and non-sedimentable activity of 8 rat liver lysosome enzymes (acid phosphatase, acid DNase, acid RNase, arylsulphatases A and B, beta-glucuronidase, beta-galactosidase, beta-glucosidase and beta-acetylglucosaminidase) was studied. Only Triton X-100 at the concentration of 0.1% (and higher) was found to release completely lysosome enzymes. Low concentrations of Triton X-100 (0.025-0.05%) were used to characterize the strength of enzyme binding: the level of releasing acid DNase, beta-galactosidase, beta-glucuronidase and acid phsophatase being considerably higher than that of other lysosome enzymes studied. On the basis of the data obtained a method is worked out, which is suitable for series studies of the stability of lysosome membranes under different physiological and pathological conditions. The essence of the method is the treatment of membrane particles with increasing concentrations of Triton X-100 (0.025; 0.05 AND 0.1%) AND THE SUCCESSIVE ESTIMATION OF NON-Sedimentable activity of marker enzymes. The method detected troubles in the stability of rat liver lysosome membranes under starvation, protein deficiency and aging.
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PMID:[Determination of lysosome membrane stability]. 120 72

Maternal protein deficiency imposed on rats a month prior to conception, and during gestation and lactation, resulted in a significant cell loss in cerebrum, cerebellum, brain stem and spinal cord of pups at weaning. The cerebellum was the most affected central nervous system (CNS) region; it contained only 25% of the normal cell number. Undernourished pups were also found to have a lower concentration of total gangliosides in cerebrum as compared to that of controls. However, the total ganglioside concentration was unaffected in the cerebellum, brain stem and spinal cord by maternal undernutrition. In all regions, undernutrition caused significant changes in the proportions of individual gangliosides; these alterations were region-specific. Sialidase, beta-galactosidase, beta-glucosidase, and beta-hexosaminidase, which are involved in the catabolism of gangliosides, showed higher activities in all the regions of undernourished pups, suggesting that these enzymes may play a role in maintaining the porportions of various ganglioside fractions.
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PMID:Maternal protein deficiency in rat: effects on central nervous system gangliosides and their catabolizing enzymes in the offspring. 194 99

The total and non-sedimentable activities of liver beta-galactosidase, beta-glucoronidase, beta-N-acetyl glucosaminidase, aryl sulfatases A and B were studied during antigenic stimulation of rats fed balanced and low-protein (5% of energy value) diets. Antigenic stimulation of rats fed a balanced diet was found to intensify the total activities of all lysosomal enzymes (up to 124-246% of control). Meanwhile protein deficiency did not cause any significant reduction in immune response and completely removed activation of lysosomal hydrolases.
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PMID:[Effect of protein deficiency and antigenic stimulation on rat liver lysosomes]. 644 Mar 54

Brain enzymes activities that are likely to be involved in the catabolism of gangliosides were determined in controls (20% casein diet), postnatally undernourished (6.5% casein diet) and undernourished rats treated with either thyroxine or hydrocortisone, at 21 days of age. Postnatal undernutrition imposed by maternal protein deficiency during lactation resulted in a decrease in body weight and brain wet weight of the pups at 21 days of age. Administration of thyroxine or hydrocortisone to the undernourished pups every day between 16 and 21 days caused a further decrease in the body weight of the pups. On the other hand, the wet weight of brain showed a slight gain following hydrocortisone treatment. Postnatal undernutrition during lactation elevated the activities of beta-glucosidase, beta-galactosidase, beta-hexosaminidase and sialidase in rat brain. Short-term administration of thyroxine or hydrocortisone to the undernourished pups, every day between 16 and 21 days postnatal age decreased the enzyme activities. However, reversal of the increased enzyme activities to the normal lower level was completed only in the case of undernourished pups treated with hydrocortisone.
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PMID:Neonatal undernutrition and short term administration of hydrocortisone and thyroxine: effects on rat brain hydrolases. 850 8