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)

The chondrocytes of the humeral epiphysis and of the articular cartilage of newborn, 8-, 30-, and 60-day-old albino rats contain beta-glucuronidase and beta-galactosidase. Both enzymes were found to be rare in the before mentioned cells. The reactions begin in the cells of the column cartilage and of the osteoblasts of the metaphysis on the 8th day of life and demonstrate an additional activity in 40- to 60-day-old animals. The results mark the activity of the degrading enzymes of the carbohydrate metabolism.
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PMID:[Age-specific distribution of beta-glucuronidase and beta-galactosidase in the humeral epiphysis of rats]. 101 45

1. Structure-linked latency, a trait for most lysosome hydrolase activities, is customarily ascribed to the permeability-barrier function performed by the particle-limiting membrane, which shields enzyme sites from externally added substrates. 2. The influence of various substrate concentrations on the reaction rate has been measured for both free (non-latent) and total (completely unmasked by Triton X-100) hydrolase activities in rat liver cell-free preparations. The substrates were: beta-glycerophosphate, phenolphthalein mono-beta-glucuronide. p-nitrophenyl N-acetyl-beta-D-glucosaminide and p-nitrophenyl beta-D-galactopyranoside. The ratio (free activity/total activity) X 100 is called fractional free activity at any given substrate concentration. 3. The fractional free activity of beta-glucuronidase and beta-N-acetylglucosaminidase were clearly independent of substrate concentration, over the range examined, in both homogenates and lysosome-rich fractions. The fractional free activity of acid phosphatase appeared to be either unaffected (homogenate) or even depressed (lysosome-rich fraction) by increasing the beta-glycerophosphate concentration. The fractional free activity of beta-galactosidase consistently showed a non-linear increase with increasing substrate concentration in both homogenates and lysosome-rich fractions. 4. Procedures such as treatment with digitonin, hypo-osmotic shock and acid autolysis, although effective in causing varying degrees of resolution of the latency of lysosome hydrolase activities, were unable to modify appreciably the pattern of dependence or independence of their fractional free activities on substrate concentration, as compared with that exhibited by control preparations. Ouabain did not affect the free beta-N-acetylglucosaminidase activity of liver homogenates at all. 5. Preincubation of control preparations with beta-glycerophosphate or p-nitrophenyl beta-galactoside did not result in any significant stimulation of the free hydrolytic activity toward these substrates. 6. The results consistently support the view that the membrane of "intact" lysosomes is virtually impermeable to all the substrates tested, except for p-nitrophenyl beta-galactoside, for which the evidence is contradictory. Moreover the progressive unmasking of the hydrolase activities produced by these procedures in vitro reflects the increasing proportion of enzyme sites that are fully accessible to their substrates rather than a graded increase in the permeability of the lysosomal membrane.
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PMID:Structural equivalents of latency for lysosome hydrolases. 104 Dec 36

The effect of the mycotoxin of Fusarium sporotrichiella v. sporotrichioides (sporofusarin) was studied in vitro on the total and nonsedimenting activity of eight lysosomal enzymes: acid ribonuclease, aryl sulfatases A and B, beta-glucuronidase, alpha- and beta-galactosidases, beta-glucosidase, beta-acetylglucosaminidase, and alpha-mannosidase. Incubation of a suspension of rat liver lysosomes with an aqueous solution of sporofusarin led to inhibition of the total activity of the membrane-bound lysosomal enzyme beta-glucosidase. In a dose of only 1.6 x 10-5 M sporofusarin caused a significant increase in the nonsedimenting activity of nearly all the enzymes; in a concentration of 1.6 x 10-3 M most of the enzymes of the lysosomal matrix (beta-glucuronidase, beta-galactosidase, aryl sulfatases A and B) were liberated almost completely into the supernatant, and nearly all the beta-glucosidase also was liberated. It is postulated that damage to the subcellular membranes is an important component of the toxic action of sporofusarin.
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PMID:Action of the mycotoxin of Fusarium sporotrichiella v. sporotrichioides on lysosomal membranes. 111 54

Cell differentiation during spermatogenesis in the rat has been analyzed in terms of the formation of specific "marker" enzymes. Hyaluronidase and other acrosomal enzymes are formed in spermatids according to a highly predictable time schedule which may be termed a "molecular biological clock". The acrosomal enzymes beta-galactosidase and N-acetyl-beta-glucosaminidase exist as isoenzyme forms distinct from enzymes with similar substrate specificities in the lysosomes of precursor cells. Differentiation of spermatids thus involves the loss of gene expression for lysosomal enzymes and the activation of genes for acrosomal isoenzymes. Spermatogenesis is characterized by the sequential loss of expression of many genes, as evidenced by the loss of beta-glucuronidase in the differentiation of spermatogonia to spermatocytes, and the loss of uridine diphosphatase activity in the differentiation of spermatocytes to spermatids. The apparent absence of ornithine decarboxylase activity from spermatids suggests a dependence of these cells upon Sertoli cells for the provision of putrescine and/or spermidine. Such biochemical cooperativity among germinal cells may be necessary as the genes of spermatids are repressed and late spermatids become metabolically inactive. Spermatogenesis is also characterized by changes in the cellular content and rates of synthesis and phosphorylation of specific acidic chromatin proteins. It is hypothesized that these proteins may participate in the activation or repression of genes during spermatogenesis.
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PMID:Gene activation during spermatogenesis. 112 12

The levels of four acid hydrolases, beta-N-acetyl glucosaminidase, beta-glucuronidase, beta-galactosidase, and acid phosphatase, and the extent of their release (release II) by thrombin was determined in platelets from nine normal subjects, nine patients with storage pool disease, and in normal platelets which had been exposed to aspirin. The levels of all four hydrolases were normal in patients with SPD. However, release of three of these hydrolases (acid phosphatase was an exception) by low concentrations of thrombin (0.015 and 0.04 U/ml) was decreased in the patients as a group, although considerable variation in the extent of release of each enzyme was noted. In contrast, aspirin failed to inhibit release II in normal platelets (except for a slight impairment in the release of beta-N-acetyl glucosaminidase), although release I (serotonin, ATP and ADP) was inhibited. All release defects could be overcome by using higher concentrations of thrombin (0.2 U/ml). The normal levels of acid hydrolases in the platelets of patients with SPD (who are deficient in the platelet dense granules) suggest that these enzymes are not normally stored in the dense granules, but rather in alpha-granules. The findings also support the conclusions of previous studies that the release reaction is impaired in SPD. This release defect appears to be different from that seen in normal platelets after exposure to aspirin.
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PMID:Content and thrombin-induced release of acid hydrolases in gel-filtered platelets from patients with storage pool disease. 113 24

We have compared the activity of the lysosomal enzymes, beta-galactosidase and beta-glucuronidase, in esophageal columnar, gastric fundic, and small intestinal epithelia. Beta-Galactosidase activity in esophageal columnar epithelium was less than that in intestinal tissue. Beta-Glucuronidase activity in the esophageal columnar epithelium was greater than that in gastric fundic tissue. Thus, this unique epithelium has enzyme characteristics which are dissimilar to both intestinal and gastric fundic tissue. This tends to support previous findings that suggested a metaplastic derivation.
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PMID:Esophageal columnar epithelial beta-galactosidase and beta-glucuronidase. 113 23

In alkali burned rabbit corneas activities of beta-glucuronidase, N-acetyl-beta-D-glucosaminidase and acid beta-galactosidase were studied histochemically in various time intervals after the traumatization. The technic with semipermeable membranes was employed. Within four days after the injury enzyme activities in the traumatized area were almost lacking. The corresponding activities in the unaffected part of the cornea were within the norm. On the 7th day enzyme activities were on an increase (but still subnormal) in the traumatized area. This area was surrounded by a zone of keratocytes with high levels of enzyme activities. This was particularly remarkable in keratocytes subjacent to the epithelium. The activation of all enzymes studied was present in the basal layer of the epithelium and in the endothelium as well. On the 14th day enzyme activities in the traumatized area were nearly restored and on the 32nd day they could not be distinguished from the normal cornea. Beta-galactosidase displayed a relatively maximal increase in the activity of all enzymes investigated.
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PMID:Alkali burns of the rabbit cornea. I. A histochemical study of beta-glucuronidase, beta-galactosidase and N-acetyl-beta-D-glucosaminidase. 119 85

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

Effect of ethanol on functional activity of isolated perfused rat liver was studied (rate of O2 utilization, absorption of bromosulpholeine from perfusate, bile formation); total activity and activity in supernatant of nine marker enzymes were also determined (malate dehydrogenase, beta-glucuronidase, arylsulphatases A and B, beta-galactosidase, beta-glucosidase, acetylesterase, glucoso-6-phosphatase, alanine aminotransferase and aspartate aminotransferase). Activity of the enzymes was simultaneously studied in perfusate. Ethanol (0.5%) caused distinct impairement in functional activity of isolated liver; rate of bile formation and absorption of bromosulpholeine from perfusate were primarily altered. Degree of impairements in functional activity of liver tissue correlated with the concentration of ethanol in perfusate. In analysis of correlation between the total activity of the enzymes in liver tissue and their activity in supernatants and perfusate it was shown that the concentration (1%) of ethanol used did not produce damaye effect on plasma membranes and membranes of subcellular structures of hepatocytes, but, within certain limits, it displayed a stabilizing effect.
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PMID:[Effect of ethanol on stability of cell membranes in experiments using isolated liver]. 121 Jan 8

A study was made of the effect of sporofusarin (mycotoxin produced by Fusarium Sporotrichiella v. Sporotrichoides) on the functional activity and permeability of cell membranes of the isolated perfused rat liver. Sporofusarin (in the end concentration of 5.9 . 10(-5) M) produced a marked depressive effect on the rate of bile, formation, urea synthesis and oxygen consumption, and also caused an early and marked disturbance of permeability of the lysosomal and plasma membranes of hepatocytes (an increase in the activity of the enzymes--beta-acetylglucosaminidase, beta-glucuronidase, arylsulfatases A and B, beta-galactosidase in the supernatant fluid of liver homogenate and in the perfusata). It is supposed that depression of the functional activity of the liver under the effect of sporofusarin resulted from damage of the membrane structures of the cell, and, primarily, of lysosomes.
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PMID:[The effect of sporofusarin on the cell membranes of isolated perfused liver]. 122 93


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