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

---

Query: EC:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The biochemical correlates of droplet formation in renal inner medullary cells of potassium-deficient rats were studied. An increase in the activities of five hydrolytic enzymes typical of lysosomes was associated with an increase in the number and size of droplets observed during progressive potassium depletion. Acid phosphatase activity increased 7-fold whereas beta-glucuronidase, beta-galactosidase, cathepsin, and acid DNase increased 2- to 4-fold in medullary homogenates at 25 days of depletion. Following potassium repletion the activities returned to normal at a rate dependent upon the duration of potassium depletion. The decreases in enzyme activities were associated with a concomitant rapid disappearance of the droplets from medullary cells. Protein synthesis for new droplet enzyme formation was studied by measuring the rate of [14C]leucine incorporation into protein in medullary slices. The rate increased at 1 day of depletion and reached a maximum which was 139 per cent higher than control after 7 days of depletion. In droplets isolated from medullary tissue during progressive potassium depletion the rate of protein labeling with [14C]leucine and acid phosphatase specific activity increased in parallel. When droplet proteins were separated by gel electrophoresis, acid phosphatase activity was detected in a protein band which had been labeled with [14C]leucine, thereby suggesting new enzyme protein formation. The increase in enzyme and protein synthesis and a previously demonstrated increase in phospholipid synthesis and membrane formation indicate that potassium depletion induces specific alterations in renal inner medullary cell metabolism which result in increased lysosome formation.
...
PMID:Formation of renal medullary lysosomes during potassium depletion nephropathy. 83 28

The catabolic phase of thyroid secretion --thyroglubulin (Tg) uptake and hydrolysis, release of hormones--has been investigated in vitro, by incubating thyroid slices with 0.1% labelled Tg, in cases of isolated adenomas. Twenty-two specimens were examined: 11 cold follicular adenomas, 5 hot nodules from euthyroid patients, 2 untreated toxic adenomas, and 4 pretreated toxic adenomas. The results were compared with those obtained in 11 specimens of normal tissue. Tg pinocytosis (the amount of Tg taken up by the slices per mg of tissue) was severely impaired in all the non-toxic nodules, cold or hot, i.e., whatever the in vivo activity of the thyroid iodide pump. In toxic adenomas, every step of the catabolic hormonogenesis was activated: high pinocytotic activity, increased Tg hydrolysis, and the discharge of hormonal products; in pretreated cases, the whole process was slowed down. Enzymic activity of the acid hydrolases, beta-galactosidase and cathepsin, was elevated in all the nodules so far investigated, particularly in the toxic adenomas.
...
PMID:Secretory activity of isolated thyroid adenomas. 94 35

3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase is a key regulatory enzyme of cholesterol biosynthesis and is located in the endoplasmic reticulum (ER). A fusion protein, HMGal, consisting of the membrane domain of HMG-CoA reductase fused to Escherichia coli beta-galactosidase and expressed in Chinese hamster ovary (CHO) cells from the SV40 promoter, was previously constructed and was found to respond to regulatory signals for degradation in a similar fashion to the intact HMG-CoA reductase. Degradation of both HMG-CoA reductase and HMGal in CHO cells was enhanced by addition of mevalonate or low density lipoprotein (LDL). In this report we show that 2 cysteine protease inhibitors, N-acetyl-leucyl-leucyl-norleucinal (ALLN) and N-acetyl-leucyl-leucyl-methioninal (ALLM), completely inhibit the mevalonate- or LDL-accelerated degradation of HMG-CoA reductase and HMGal and also block the basal degradation of these enzymes. It has been shown that in vitro these protease inhibitors inhibit the activities of Ca(2+)-dependent neutral proteases as well as lysosomal proteases, including cathepsin L, cathepsin b, and cathepsin D. However, the mevalonate-accelerated degradation of HMG-CoA reductase and HMGal is not affected by lysosomotropic agents, suggesting that the site of action of these inhibitor peptides in preventing the degradation is not the cathepsins. In brefeldin A-treated cells, where protein export from the ER is blocked, ALLN is still effective in inhibiting the degradation of HMG-CoA reductase and HMGal. These results indicate the involvement of non-lysosomal Ca(2+)-dependent proteases in the basal and the accelerated degradation of HMG-CoA reductase and HMGal. Enzymatic assays in vitro and immunoblot analyses have revealed calpain- and calpastatin-like proteins in CHO cells. The activities and the amount of these proteins do not change under conditions of enhanced degradation, indicating that the levels of these proteins are not subject to mevalonate regulation.
...
PMID:Inhibition of degradation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase in vivo by cysteine protease inhibitors. 190 66

The changes in the activities of certain lysosomal hydrolases, viz., beta-glucuronidase, beta-N-acetylglucosaminidase, beta-galactosidase, beta-glucosidase, alpha-glucosidase, alpha-galactosidase, alpha-mannosidase, cathepsin B, cathepsin D, and collagenolytic cathepsin, in serum and heart of rats subject to myocardial infarction with isoproterenol, were studied during the periods of peak infarction and recovery. The activities of all the enzymes assayed exhibited a significant increase both in serum and in heart at peak infarction stage and these levels returned to normal during the stage of recovery and repair. The infiltration of inflammatory cells at the infarct regions and the altered lysosomal fragility are probably responsible for the increased activity of the enzymes studied. This may also bring about the catabolism of connective tissue constituents as reported in literature.
...
PMID:Influence of isoproterenol-induced myocardial infarction on certain glycohydrolases and cathepsins in rats. 201 10

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.
...
PMID:Selective presence of acid hydrolases in the interphotoreceptor matrix. 261 85

Activation of proteolysis by ATP was studied in lysates of crude and purified lysosomal preparations from liver and kidney at acid pH. In the crude system, from kidney, it was found that ATP activates proteolysis over a concentration range of 0.1-2 mM. Up to 4-fold activation was observed. GTP and CTP also activated proteolysis, but to a lesser extent. Proteolysis was inhibited by vanadate and molybdate. Fractionation of the kidney lysosomes on Percoll gradients produced two fractions containing lysosomal marker enzymes. Most of the acid phosphatase and the acid pyrophosphatase were found in the lighter band, while most of the beta-galactosidase and cathepsin activity was found in a more dense band. Proteolysis by lysates of both fractions was activated by ATP and inhibited by vanadate and molybdate. In the dense band proteolysis was also nearly totally blocked by pepstatin, and was enhanced by an inhibitor of pyrophosphatases, sodium fluoride. ATP also activates proteolysis in crude lysosomes from liver, but upon fractionation of this tissue it was found that all the lysosomal enzyme markers are present in the dense fraction obtained from the Percoll gradient. Again, proteolysis by lysates of the purified fractions was activated by ATP and inhibited by vanadate and molybdate. These data indicate that ATP can activate proteolysis at acid pH in a lysosomal milieu containing enzymes which also catalyze its breakdown. In the kidney there may be two lysosomal compartments which separate the enzymes catalyzing ATP breakdown from the proteolytic enzymes, but this is not essential for ATP activation as shown by the data from the liver and the crude lysosomal fractions.
...
PMID:ATP activation of protein degradation by extracts of crude and purified lysosomal preparations. 385 74

Rat mammary tumours induced by 7,12-dimethylbenz[a]anthracene can undergo repeated growth and regression during successive pregnancies. In a 10-day period after birth about half of the tumours regressed 50% or more. The concentrations of the lysosomal enzymes increased in regressing mammary tumours to the following multiples of the initial values: beta-glucuronidase, 7.7; beta-galactosidase, 3.9; cathepsin, 2.9; acid ribonuclease, 2.1; arylsulphatase A, 1.5; acid phosphatase, 1.4. In contrast, several non-lysosomal enzymes failed to increase. Activities in the post-partum uterus increased to the following multiples of the initial values: beta-glucuronidase, 5.8; cathepsin, 5.5; acid ribonuclease, 4.3; beta-galactosidase, 2.2; acid phosphatase, 1.8. Arylsulphatase A in the post-partum uterus decreased significantly, suggesting a non-lysosomal distribution or a special function related to pregnancy. No other significant changes were observed in the lysosomal or non-lysosomal enzymes in the hormone-independent liver or hormone-dependent normal mammary gland. The ratio of free to bound arylsulphatase A and acid ribonuclease decreased slightly 1-3 days after birth because of problems in homogenizing the tumours. At days 4-8, however, there was a dramatic increase in the ratio of the free to bound activities. The results can be explained in terms of the lysosomal theory of intracellular digestion.
...
PMID:Lysosomal enzyme changes in growing and regressing mammary tumours. 576 57

1. The rat uterus contains acid cathepsin, beta-glucuronidase, beta-galactosidase, acid phosphatase and deoxyribonuclease II at concentrations comparable with those found in liver. Two non-hydrolytic uterine enzymes, cytochrome c oxidase and aspartate aminotransferase, display only 2-6% of the activity found in liver. 2. The concentrations of acid cathepsin and beta-glucuronidase are significantly decreased in pregnancy and increase 3-4-fold during post-partum involution. 3. The concentrations of beta-galactosidase and acid phosphatase are not decreased in pregnancy and increase only 2-3-fold during involution. 4. The concentrations of these four acid hydrolases increase linearly during the first 4 days post partum and reach their peak values at the same time that wet weight and collagen content fall to their lowest point. 5. The concentration of deoxyribonuclease is depressed in pregnancy but does not rise above normal in the post-partum period. 6. Only a small proportion of each hydrolytic activity can be isolated in the mitochondrial-lysosomal fraction of sucrose homogenates of the rat uterus. This proportion increases during involution. However, the extensive mitochondrial rupture occurring during homogenization indicates that the technique is probably too harsh to obtain a true measure of the proportion of lysosomes present in the intact tissue. 7. There are no significant changes in either the concentration or subcellular distribution of the five acid hydrolases in the livers of the experimental rats during pregnancy or involution. In each case the largest proportion of the activity is found in the mitochondrial-lysosomal fraction of liver homogenates. 8. The results are interpreted in terms of the lysosomal theory of intracellular digestion.
...
PMID:Acid hydrolases of the rat uterus in relation to pregnancy, post-partum involution and collagen breakdown. 589 45

Administration of cycloheximide (0.1-0.4 mg/kg bw) to rats caused a progressive drop of cathepsin A, B, C and D activity in the liver and kidneys. In the spleen, the activity of all lysosomal proteinases declined 50-70% even with the minimal dose of cycloheximide. On the contrary, the activity of other lysosomal hydroxylases (beta-galactosidase and arylsulfatases A and B) dropped by not more than 10-25% in all the organs under study, regardless of the fact that the dose of cycloheximide was maximal. It is suggested that the reduction of cathepsin activities during protein biosynthesis inhibition is a regulatory mechanism by which the protein resources in the cell are preserved.
...
PMID:[Effect of cycloheximide on lysosomal proteinase activity in rat organs]. 613 63

BCG lesions were produced in the skin of rabbits, and biopsies were performed at 7, 21, and 42 days, when they were developing, maximal in size, and almost healed, respectively. Tissue sections were prepared and stained histochemically for several enzymes. The percentage of cells stained for a given enzyme and the distribution of such cells within lesions of various ages were determined. Seven-day BCG lesions contained few esterase- and beta-galactosidase-positive macrophages, but 21-day lesions contained many, especially in the viable and nonviable tuberculous granulation tissue at the edge of the now prominent caseous necrotic center. Both 7-day and 21-day lesions contained many acid phosphatase- and cathepsin-D-positive macrophages, which were numerous in the more peripheral parts of the lesion, where little or no necrosis was present. Enzyme patterns in 42-day lesions resembled those in 21-day lesions. The role of each of these enzymes in the development and regression of the BCG lesion is unknown. Nonetheless, these studies clearly demonstrate that this macrophage population is heterogeneous and that macrophages carry out different functions in different parts of the lesion at different times. Histochemical techniques were developed to stain two enzymes in the same tissue section. The first stain usually contained a naphthol substrate and produced a red color; the second stain contained an indoxyl substrate and produced a blue color. A cell staining with both was colored purple. The peroxidase-antiperoxidase immunocytochemical technique for cathepsin D (producing a red color) was also employed. 1) Red esterase (hydrolyzing naphthol AS-D acetate) and beta-galactosidase, and 2) red esterase and blue esterase (hydrolyzing 5-bromo-4-chloro-indoxyl acetate), probably the same enzyme, were usually present in the same macrophage. In contrast, each of the following enzyme pairs was usually present in a different macrophage: 3) cathepsin D and beta-galactosidase, 4) cathepsin D and blue esterase, 5) acid phosphatase and beta-galactosidase, and 6) acid phosphatase and blue esterase. Roughly 10% of the macrophages stained for one enzyme existed side by side with macrophages stained for a different enzyme. These results suggest that local macrophage activation is under two levels of control. The first, macrolocal control, would determine the overall enzyme distribution in the lesion; whereas the second, microlocal control, would determine enzyme distribution on a cell-by-cell basis, ie, how two neighboring macrophages can each be rich in a different enzyme.
...
PMID:Macrophage functional heterogeneity in vivo. Macrolocal and microlocal macrophage activation, identified by double-staining tissue sections of BCG granulomas for pairs of enzymes. 615 72


1 2 3 Next >>

---