Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Adult rats when fed a high carbohydrate diet of 70% sucrose or glucose for 24 h following a 4-day fast showed increased concentrations of intestinal sucrase-isomaltase (EC 3.2.1.48, EC 3.2.1.10) and maltase-glucoamylase (EC 3.2.1.20) but not lactase-phlorizin hydrolase (EC 3.2.1.23, EC 3.2.1.62). The concentration increases of these enzymes were accompanied by corresponding acceleration of their synthesis rates. Contrary to earlier studies by others, suggesting that upper villus cells in the fasted intestine are unresponsive to stimulation of sucrase activity by refeeding a high-sucrose diet, the concentration increases of both sucrase-isomaltase and maltase-glucoamylase were seen to occur in cells all along the length of the villus column. The earlier studies differed from the present study by basing enzyme assays relative to protein rather than the DNA content of villus cell fractions. We have shown that villus cells increase their protein content severalfold while migrating to villus tip, providing the basis for the difference between earlier and the present findings. Further evidence that stimulation of sucrase-isomaltase and maltase-glucoamylase by high carbohydrate is not restricted to the crypt and lower villus region was obtained by the finding that their synthesis rates appeared to be equally stimulated along the length of the villus column.
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PMID:Dietary CHO and stimulation of carbohydrases along villus column of fasted rat jejunum. 249 55

One of the final steps in epidermal differentiation is the conversion of glucosylceramides to ceramides, which presumably is mediated by a beta-glucosidase activity. In the present manuscript, it is demonstrated that pig epidermis contains beta-glucosidase activity which is 3.3-times greater than alpha-glucosidase and 5-times greater than beta-galactosidase. This beta-glucosidase was found to be maximally active between pH 3.0 and essentially inactive at pH 9.0. In a standard assay, a disk of epidermis (8 mg dry weight) was submerged in 1 ml of 50 mM acetate buffer (pH 4.7) containing 150 mM NaCl and 15 mM p-nitrophenyl-beta-D-glucopyranoside at room temperature. Reaction was stopped by addition of 4 ml of 100 mM (pH 9.0) borate buffer and the supernatant was transferred to a separate tube. The nitrophenylate anion was then measured spectrophotometrically at a wavelength of 405 nm. Under these conditions, product formation was linear for at least 90 min and an apparent Km of 244 microM was estimated for the synthetic substrate. When the amount of epidermis in the assay was varied, the formation of product per unit of time remained proportional to the amount of epidermis. The level of beta-glucosidase activity was enhanced slightly by the inclusion of sodium taurocholate.
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PMID:Beta-glucosidase activity in porcine epidermis. 249 22

Australine [(1R,2R,3R,7S,7aR)-3-(hydroxymethyl)-1,2,7-trihydroxypyrrolizid ine] is a polyhydroxylated pyrrolizidine alkaloid that was isolated from the seeds of the Australian tree Castanospermum australe and characterized by NMR and X-ray diffraction analysis [Molyneux et al. (1988) J. Nat. Prod. (in press)]. Since swainsonine and catanospermine are polyhydroxylated indolizidine alkaloids that inhibit specific glycosidases, we tested australine against a variety of exoglycosidases to determine whether it would inhibit any of these enzymes. This alkaloid proved to be a good inhibitor of the alpha-glucosidase amyloglucosidase (50% inhibition at 5.8 microM), but it did not inhibit beta-glucosidase, alpha- or beta-mannosidase, or alpha- or beta-galactosidase. The inhibition of amyloglucosidase was of a competitive nature. Australine also inhibited the glycoprotein processing enzyme glucosidase I, but had only slight activity toward glucosidase II. When incubated with cultured cells, this alkaloid inhibited glycoprotein processing at the glucosidase I step and caused the accumulation of glycoproteins with Glc3Man7-9(GlcNAc)2-oligosaccharides.
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PMID:Australine, a pyrrolizidine alkaloid that inhibits amyloglucosidase and glycoprotein processing. 249 72

Small-intestinal disaccharidase activities of eight suckling T. vulpecula, aged from 34 to 150 days, and of two adult animals were investigated. Intestinal maltase, isomaltase and sucrase activities increased with age, whereas lactase activities decreased. Trehalase activities were relatively high in all animals and showed no obvious age-related changes. Three separate beta-galactosidase activities, one neutral and two acid, acted on lactose. The neutral beta-galactosidase activity appeared to be due to a brush border enzyme similar to that of eutherian mammals, whereas the acid beta-galactosidases were soluble and probably of lysosomal origin. One of these, acid beta-galactosidase-1, had similar properties to the sole intestinal beta-galactosidase of macropodid marsupials, whereas the other, acid beta-galactosidase-2, has not previously been described. Galactosyl oligosaccharides isolated from macropodid milk were readily hydrolysed by both acid beta-galactosidases but not by the neutral beta-galactosidase. The total intestinal lactase activity in animals aged up to 125 days was due mainly to acid beta-galactosidase-1, whereas in older animals it was due mostly to the neutral beta-galactosidase; this suggests that late in lactation the young T. vulpecula change from a macropodid mode of digestion of galactosyl oligosaccharides to a eutherian mechanism for the digestion of lactose. These findings may have implications for the hand-rearing of orphaned T. vulpecula.
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PMID:Intestinal lactase (beta-galactosidase) and other disaccharidase activities of suckling and adult common brushtail possums, Trichosurus vulpecula (Marsupialia:Phalangeridae). 251 66

Adler and Martin (1983, Curr. Eye Res. 2, 359-66) found cathepsin D to be present in crude preparations of bovine interphotoreceptor matrix (IPM). The purpose of the present study was to determine, by investigating several acid hydrolases in purer IPM samples, whether hydrolytic enzymes abundant in RPE lysosomes were present also as normal components of the IPM. IPM was prepared from bovine eyes by the introduction of a small bleb of buffer between the neural retina and the RPE. These IPM samples were free from significant contamination by surrounding tissues; they contained IRBP as their only major protein, and had negligible amounts of lactate dehydrogenase and ROS-specific proteins. Most acid hydrolases were assayed fluorometrically by measuring the 4-methylumbelliferone released upon hydrolysis of appropriate derivatives; the substrate for cathepsin was hemoglobin. The amounts of the enzymes found in the IPM were far from uniform and could not be correlated with enzyme activities in either RPE or retina homogenates. The hydrolases in the IPM varied in amount from beta-galactosidase (28% of the RPE level), through N-acetyl-beta-glucosaminidase (20%), alpha-fucosidase (15%), beta-glucuronidase (12%), alpha-glucosidase (8%), cathepsin D (7%), alpha-mannosidase (7%), down to beta-glucosidase, acid phosphatase, and acid lipase (trace amounts, less than 1%). These results agree with the relative amounts of enzymes found by Wilcox (1987) to be secreted into the medium by cultured human RPE cells. Furthermore, the rank order of hydrolases in the IPM is the same as that for hydrolases secreted (but not recaptured) by human fibroblasts in I-cell disease. The conclusion from these correlations is that lysosomal enzymes are probably secreted, as a normal process, by the RPE into the IPM, where they may have a role in digesting shed outer segments and in catabolizing IPM components.
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PMID:Selective presence of acid hydrolases in the interphotoreceptor matrix. 261 85

Human intestinal bacteria were grown in a 3-stage continuous culture system on a medium containing complex polysaccharides and proteins as carbon and nitrogen sources. Selected bacterial populations were enumerated and glycosidase, protease and arylamidase activities measured. Comparison of arylamidase and glycosidase activities in the multichamber system (MCS) and faeces showed that the predominant faecal enzymes were also produced by bacteria growing in the MCS. After 48 d operation, porcine gastric mucin (5.8 g/d) was independently fed to vessel 1. Elevated levels of volatile fatty acid (VFA) formation showed that the glycoprotein was actively fermented. The increase in carbohydrate availability as a result of breakdown of the mucin oligosaccharides stimulated bacterial growth and activities. The enzymological measurements showed that mucin increased production of both cell-bound and extracellular glycosidases, such as beta-galactosidase, alpha-glucosidase and N-acetyl-beta-glucosaminidase. Protease activities were profoundly influenced by mucin. These were largely cell-bound in non-mucin cultures but were predominantly extracellular and collagenolytic when mucin was present. Experiments with protease inhibitors showed that cysteine proteases were the major cell-bound and extracellular enzymes in both mucin and non-mucin cultures, but that serine and metalloproteases were also present. The effect of mucin on arylamidase formation was less marked, although there was increased production of these enzymes in vessels 1 and 2 of the MCS. These results suggest that host-produced substances such as mucin glycoprotein may play a role in modulating the growth and activity of bacteria growing in the human large intestine.
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PMID:Influence of mucin on glycosidase, protease and arylamidase activities of human gut bacteria grown in a 3-stage continuous culture system. 266 79

Normal arterial foci which take up Evans blue dye (EBD) in vivo are believed to represent atherosclerosis-prone, hemodynamically stressed foci compared to areas which exclude dye. We have used the rabbit EBD model to examine focal aortic hydrolases of blue areas versus white areas, and we report herein significant focal variations of hydrolase activities. Enzymes measured included neutral alpha-glucosidase, N-acetyl-beta-glucosaminidase, alpha-mannosidase, acid alpha-glucosidase, beta-galactosidase, beta-glucuronidase, cathepsin C, and acid cholesteryl esterase (ACE); specific activities were expressed on the basis of tissue DNA. In correlative areas of EBD uptake in normal rabbit aortic arch, ACE activity averaged 17% higher and cathepsin C activity averaged 37% lower than activities of areas free of EBD in the descending thoracic aorta (P less than 0.02). None of the glycosidases studied differed significantly between blue and white aortic areas. These findings indicate that discrete, intrinsic differences of hydrolytic enzyme activities exist in the normal rabbit aorta in areas delineated by in vivo EBD uptake, areas recognized as lesion-prone vs lesion-resistant.
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PMID:Intrinsic focal variations of rabbit aortic hydrolase activities. 276 19

Flavonoids (103 species) were tested for inhibitory activity against mouse liver sialidase using sodium p-nitrophenyl-N-acetyl-alpha-D-neuraminate (PNP-NeuAc) as substrate. Isoscutellarein-8-O-glucuronide from the leaf of Scutellaria baicalensis showed most potent activity (IC50, 40 microM), and this flavone appeared to be a non-competitive inhibitor of the enzyme. This flavone inhibited the lysosomal solubilized sialidase against PNP-NeuAc and sialyllactose effectively, but not microsomal enzyme against gangliosides and colominic acid, whereas, negligible or weak inhibitory activities were observed for influenza virus sialidase, beta-galactosidase, alpha-mannosidase, and alpha-glucosidase tested. These results indicate that this flavone may be useful to elucidate the function of the lysosomal solubilized sialidase.
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PMID:Inhibition of mouse liver sialidase by plant flavonoids. 277 64

Various lysosomal acid hydrolases from tissues of Niemann-Pick mice, a mutant strain of C57BL/KsJ mice (spm/spm), were examined and compared to those from control mice. Activities of beta-hexosaminidase, beta-galactosidase, acid phosphatase, and cathepsin L were elevated in the liver and spleen of the affected mice, whereas no significant changes in beta-glucosidase and acid alpha-glucosidase were observed. Alpha-Mannosidase and neutral alpha-glucosidase activities were rather decreased in the affected mouse liver. The level of beta-hexosaminidase in the Niemann-Pick mice was raised sixfold in the liver and two- to threefold in the spleen and brain, whereas its total activity was decreased in the kidney. Sixty to ninety percent of total activity of lysosomal hydrolases was solubilized with 0.1% Triton X-100 in control mice, but most of the beta-hexosaminidase activity of the Niemann-Pick mice remained associated with the membrane fraction of liver lysosomes. The beta-hexosaminidase of the Niemann-Pick mice was appreciably stable when heated at 55 degrees C, while hydrolases of the affected mice and all of the enzymes tested in control mice were heat labile. The relative content of two beta-hexosaminidase fractions separated by DEAE-cellulose column chromatography was 8% for beta-hexosaminidase I and 92% for beta-hexosaminidase II in the case of the control mouse liver. The isozyme pattern of hexosaminidases in Niemann-Pick mice was similar to that of control enzymes. However, the beta-hexosaminidase II accumulated in Niemann-Pick mouse liver was different from that of the control in optimum pH, Km values and thermostability.
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PMID:Properties of lysosomal beta-hexosaminidase accumulated in Niemann-Pick mouse liver. 294 29

A number of lysosomal enzymes are secreted from Tetrahymena pyriformis during growth and during starvation. The secretion is energy-dependent and kinetically different among hydrolases. On the basis of the secretion kinetics under starvation conditions, Tetrahymena hydrolases can be separated into three classes. The first group containing acid phosphatase, beta-glucosidase and alpha-galactosidase, are secreted slowly. Within this group about 4% of the initial cellular activity is released per hour. The second group of enzymes, including alpha-glucosidase, alpha-mannosidase and beta-galactosidase, exhibit moderate secretion (11-15% of the initial cellular activity per hour). The third group, N-acetyl-beta-hexosaminidase, has the highest rate of secretion (22% of the initial cellular activity per hour). N-Acetyl-beta-hexosaminidase shows a continuous increase in overall activity during starvation, which is completely blocked by adding cycloheximide; its secretion is also suppressed. Such involvement of enzyme biosynthesis was not seen in the first and second groups. Furthermore, treatment with weak bases caused inhibited secretion of differing degree among acid phosphatase (group I), alpha-glucosidase (group II) and N-acetyl-beta-hexosaminidase (group III).
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PMID:Secretion heterogeneity of lysosomal enzymes in Tetrahymena pyriformis. 295 37


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