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:3.2.1.20 (alpha-glucosidase)
4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The subcellular distribution of nine glycosidases were studied in fractions of homogenized human polymorphonuclear leucocytes (neutrophils) obtained by isopycnic centrifugation through linear sucrose density gradients. The substrates were 4-methylumbelliferyl glycosides. All nine glycosides were hydrolysed by enzymes in neutrophil cytosol fractions, and by enzymes in at least one granule population. alpha-Glucosidase activity sedimented in sucrose density gradients to a point (p = 1.180 g/ml) just above the specific granules, possibly the 'tertiary' granule population. The peak corresponding to alpha-glucosidase did not co-sediment with, but considerably overlapped, the peak corresponding to lactoferrin, a marker for specific granules (p = 1.187 g/ml). alpha-Galactosidase activity was found primarily in heavy azurophil granules (p = 1.222 g/ml). alpha-Mannosidase activity was found primarily in light azurophil granules (p = 1.206 g/ml), following the distribution of myeloperoxidase, the commonly used azurophil granule marker. beta-Glucosidase activity was concentrated in mitochondrial fractions (p = 1.160 g/ml). All other glycosidases presented complex distributions, with activities not restricted to one granule class. Granule-associated glycosidase activities were increased 2--38 times when measured in the presence of 0.05% Triton X-100, indicating latency of the enzymes within granules.
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PMID:Subcellular distribution of glycosidases in human polymorphonuclear leucocytes. 2 8

The brush border of normal small-intestine epithelial cells is rich in enzymes that are involved in the digestive process. Such molecules can be used as markers to analyze cell lineages and differentiation properties of colorectal cancers. Monoclonal antibodies detecting dipeptidyl peptidase-IV, aminopeptidase N, endopeptidase F, sucrase-isomaltase, alkaline phosphatase, maltase-glucoamylase and lactase have been used to analyze the phenotype of colorectal cancers, adjacent mucosa and histologically normal distant mucosa. The avidin-biotin peroxidase complex method was used. Expression of dipeptidyl peptidase-IV, aminopeptidase N, sucrase-isomaltase and alkaline phosphatase was common in non-neoplastic mucosa adjacent to, and distant from, the tumor; in contrast, endopeptidase F, maltase-glucoamylase and lactase were rarely expressed in normal distant mucosa and more frequently expressed in mucosa adjacent to the tumor. Dipeptidyl peptidase-IV, aminopeptidase N, endopeptidase F, sucrase-isomaltase and alkaline phosphatase were frequently expressed in colorectal cancers, whereas maltase-glucoamylase and lactase were rarely expressed. Two general patterns of antibody reactivity were observed: diffuse cytoplasmic and apical; apical reactivity was generally associated with more differentiated tumors. A logistic predictive regression model indicated that enzyme expression in colorectal cancers followed a coordinate pattern, but was unrelated to the location of the tumor, Dukes stage or differentiation grade. In conclusion, expression of brush-border-associated enzymes occurs frequently in colorectal cancers and is regulated in a co-ordinated manner. These markers can be used for the phenotypic sub-classification of colorectal cancers.
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PMID:Intestinal brush-border-associated enzymes: co-ordinated expression in colorectal cancer. 134 6

Two methods for specifically detecting maltase, alpha-glucosidase, or isomaltase activity in electrophoresis gels are described. Both systems couple the formation of glucose by enzyme action on maltose or isomaltose to the generation of a colored product. System A uses an agarose overlay which contains substrate, glucose oxidase, peroxidase, 2,4-dichlorophenol, and 4-L-amino-phenazone. A purple color is produced at the site of enzyme activity. No hazardous chemicals are used at any stage. The stain is simple, rapid, sensitive, and inexpensive and does not interfere with subsequent protein staining. However, the stain is not permanent. System B was developed to give a permanent stain. The gel is overlaid with agarose containing substrate, glucose oxidase, phenazine methosulfate, and nitroblue tetrazolium. Glucose production results in the nitroblue tetrazolium being oxidized to an insoluble formazan with a dark blue color. This stain is also sensitive, rapid, and inexpensive but does use hazardous chemicals and if overstaining occurs this can interfere with subsequent protein staining. Neither system inactivates the localized enzymes which can be recovered from the gel if desired.
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PMID:Two staining methods for selectively detecting isomaltase and maltase activity in electrophoresis gels. 169 32

We studied glycogen storage in the developing airway epithelium of Syrian golden hamsters from gestational Day 11 to neonatal Day 2 using concanavalin A (ConA) staining as an adjunct approach to the periodic acid-Schiff (PAS) reaction. One hundred and fourteen fetuses and neonates were fixed in 4% formaldehyde-1% glutaraldehyde, 6% mercuric chloride-1% sodium acetate-0.1% glutaraldehyde, and 95% ethanol, embedded in paraffin, and stained with ConA-horseradish peroxidase conjugate as well as with PAS. ConA staining was abolished by alpha-glucosidase digestion or by pre-treatment with periodic acid, demonstrating that ConA bound to glycogen. In tissues fixed with mercury and/or aldehydes, ConA staining was greatly enhanced by pepsin digestion. Airway glycogen stores, revealed by ConA and PAS, fluctuated during development. At first all the undifferentiated epithelial cells contained abundant glycogen. Then, coincident with the appearance of the first endocrine cells, the glycogen stores were depleted. Thereafter, glycogen accumulated in pre-secretory and basal cells until birth, but by 2 days after birth the glycogen stores were again depleted. The initial depletion of glycogen followed by repletion was observed at all levels of the conducting airways; changes in the trachea preceded those in the bronchi and bronchioles by 1 and 2 days, respectively.
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PMID:Modulation of glycogen stores in epithelial cells during airway development in Syrian golden hamsters: a histochemical study comparing concanavalin A binding with the periodic acid-Schiff reaction. 233 26

The nature of the cytoplasmic coat present on the apical invaginations of the kidney proximal tubule cell was investigated by immuneoverlay and immunocytochemistry of renal brush borders with anticlathrin antibodies. When kidney cortex was prepared for electron microscopy using methods that enhance visualization of clathrin coats, the apical invaginations at the base of the brush border microvilli were seen to be backed by a nearly continuous coating which resembles but is more extensive than the lattice-like clathrin coats found around brain coated vesicles. When isolated brush border fractions were prepared under conditions that preserve the coats, separated by SDS PAGE, and transferred to nitrocellulose, the presence of clathrin heavy and light chains was detected by immuneoverlay using two different affinity-purified anticlathrin IgGs--one that we prepared, which detects only the clathrin light chains, and the other, prepared by Louvard et al. ( Louvard , D., C. Morris, G. Warren, K. Stanley, F. Winkler , and H. Reggio , 1983, EMBO [Eur. Mol. Biol. Organ.] J., 2:1655-1664), which detects both the heavy and light chains. As viewed by light microscopy (immunofluorescence or immunoperoxidase), staining with both anticlathrins was concentrated at the base of the proximal tubule microvilli. Immunoelectron microscopic localizations carried out on brush border fractions (using peroxidase and gold conjugates) demonstrated specific binding of anticlathrin IgGs to the lattice-like cytoplasmic coat. When brush border fractions were reacted with monoclonal antibodies prepared against gp330 and maltase, proteins that serve as markers for the membrane of the apical invaginations and microvilli, respectively ( Kerjaschki , D., L. Noronha - Blob , B. Sacktor , and M. G. Farquhar , 1984, J. Cell Biol., 98:1505-1513), the two proteins retained their restrictive distribution in the brush border. The findings demonstrate (a) that the cytoplasmic coat of the proximal tubule intermicrovillar apical invaginations is composed of clathrin heavy and light chains, and (b) that the differential distribution of proteins in these two brush border microdomains is maintained in appropriately prepared brush border fractions.
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PMID:Presence of an extensive clathrin coat on the apical plasmalemma of the rat kidney proximal tubule cell. 637 81

The binding of the lectins concanavalin A (Con A) and wheat germ agglutinin (WGA) to the luminal surface of lung alveolar epithelial cells was compared in normal rats and rats with streptozotocin-induced diabetes and their offspring. Lung tissue was lavaged, then fixed in situ with 3% glutaraldehyde. Buffer-rinsed slices of lung were incubated in Con A, WGA, or various control media. Lectin binding sites were visualized by the use of the peroxidase method. Normal neonates and those that were the results of diabetic pregnancies showed a hexose-specific Con A and WGA binding pattern qualitatively similar to that of normal and diabetic adults, respectively. In the normal animals, Con A binding sites were masked by sialic acid residues and were removable with alpha-mannosidase after neuraminidase treatment. In the diabetic adults and their offspring, one the other hand, Con A binding sites were readily accessible and were totally removed only by sequential treatment with alpha-mannosidase and alpha-glucosidase. WGA binding was essentially eliminated with neuraminidase in all animals except in the neonates from diabetic pregnancies, where N-acetyl-glucosaminidase was also required. The effects of maternal diabetes were reversible and occurred about Day 7 postpartum in the neonate. The effects were also reversible following insulin replacement in the diabetic adult.
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PMID:Diabetic pregnancy. Changes in lectin binding to the surface of rat lung alveolar epithelial cells. 668 9

Acid alpha-glucosidase (E.C. 3.2.1.3) was purified more than 60,000-fold from rat liver. Antibody was obtained by injection of this pure enzyme into rabbits with Freund's complete adjuvant. The resultant anti-acid alpha-glucosidase immunoglobulin (Ig) G was digested with pepsin and then F(ab')2 was treated with 2-mercaptoethanol. Coupling of Fab' to horseradish peroxidase was performed according to the method of Wilson and Nakane. Light microscopic observation of the immunohistochemical localization of this enzyme in rat hepatocytes revealed small granular deposits of diaminobenzidine reaction products. The reaction diffusely observed in the hepatocyte cytoplasm of any area. Under the electron microscope, the reaction precipitates were found to be located on the lysosome membrane, particularly on the inner side of the membrane, as small dots. The small vesicles were strongly positive for this reaction. Occasionally positive reaction were also demonstrated in the lumen of the secondary lysosomes. However, the Golgi and its associated structures did not show a positive reaction.
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PMID:Immunohistochemical localization of acid alpha-glucosidase in rat liver. 703 44

Premature infants are susceptible to intestinal ischemia during the newborn period when their intestinal tracts are functionally and structurally immature. Studies have shown that exogenous glucocorticoids hasten intestinal maturation. We investigated the effects of hydrocortisone on platelet activating factor (PAF)-induced intestinal ischemia in the neonatal rat. On Postnatal Days 7-11, Sprague-Dawley rats were given intraperitoneal (ip) injections of either saline (SAL) or hydrocortisone (HC; 50 mg/kg total). On Day 12, rats were injected with either PAF (2 micrograms/kg) or an equal volume of saline. After 2 hr the rats were sacrificed and sections were taken for histology. The remaining intestine was analyzed for maltase, lactase, myeloperoxidase (MPO), and xanthine oxidase (XO). Experimental groups were as follows: SAL (N = 8), received saline only; SAL+PAF (N = 8), received saline plus PAF; HC (N = 3), received hydrocortisone+saline; and HC+PAF (N = 5), received hydrocortisone plus PAF. XO was significantly decreased (P < 0.001) in the hydrocortisone-treated groups (HC + SAL = 16.36 +/- 18.42 units/g protein, HC + PAF = 17.33 +/- 9.06 units/g protein) vs the controls (SAL only = 108.90 +/- 20.24 units g/protein, SAL + PAF = 145.77 21.28 units/g protein). MPO was not significantly elevated in SAL + PAF (4.60 +/- 0.95 units/g protein) vs HC + PAF (2.18 +/- 0.80 units/g protein) in this study. Maltase was significantly elevated (P < 0.001) in the HC + PAF (241.46 +/- 40.6 mole/min/g protein) and HC + SAL (152.78 +/- 16.35 mole/min/g protein) vs saline only (28.35 +/- 5.77 mole/min/g protein and SAL + PAF (37.29 +/- 8.70 mole/min/g protein. Animals (7/8) in the SAL + PAF group developed ischemia by inspection and histologic exam.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Intestinal ischemia in the newborn: the role of intestinal maturation. 824 92

We have assessed the effect of the oral ingestion of thioacetamide on small intestine structure and function. Thioacetamide-treated rats showed diminished mucosa weight; protein, DNA, and RNA content; and leucine aminopeptidase activity as compared to controls in both jejunum and ileum. In the jejunum, there was a reduction in the activities of alkaline phosphatase, ATPase, glucose-6-phosphatase, and myeloperoxidase, whereas in the ileum, maltase, lactase, and gamma-glutamyltranspeptidase were reduced. In both jejunum and ileum we found enlarged intercellular spaces, dark epithelial enterocytes, and lymphocyte infiltration. Enterocytes showed lobulated nuclei, deranged mitochondria with loss of their cristae, dilated rough endoplasmic reticulum containing dense material, and vesiculation of the smooth endoplasmic reticulum and the Golgi apparatus. Smooth muscle cells of the intestine exhibited ultrastructural alterations. These findings indicate that chronic oral intake of thioacetamide mimics not only hepatic alterations but also small intestine alterations normally associated with human cirrhosis.
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PMID:Hepatotoxic agent thioacetamide induces biochemical and histological alterations in rat small intestine. 928 39

Measurement of alpha-glucosidase (alpha-GLUC) activity by means of a simple colorimetric test using a commercial kit (EpiScreen; FertiPro, Lotenhulle, Belgium) yielded results that were strongly correlated with the values obtained for the neutral iso-enzyme measured by a fluorimetric reference method (r=0.85, P=0.003, n=13). The former method was characterized by a low intra- and inter-coefficient of variation (6.6 and 4.3% respectively). Vasectomized men with azoospermia (n=27) had a significantly lower alpha-GLUC activity in semen than vasectomized men with residual spermatozoa present (n=11, P < 0.01) and men with azoospermia of primary testicular origin (n=33, P < 0.01). Receiver operating curve (ROC) analysis showed alpha-GLUC measurement to be reasonably accurate in differentiation between cases with obstructive versus testicular azoospermia at criterion value 13.5 U/l (sensitivity=82%, specificity= 70%). In cases with spermatozoa present, alpha-GLUC activity and output per ejaculate were positively correlated with sperm concentration (r=0.53 and 0.38, n=472), linear velocity (r=0.35 and 0.30, n=224), curvilinear velocity (r=0.32 and r=0.29, n=224), semen adenosine triphosphate (r=0.35 and 0.26, n=64), the concentration of 5alpha-dihydrotestosterone (r=0.31 and 0.29, n=74), and gamma-glutamyltransferase activity (r=0.62 and 0.32, n=275) in seminal plasma. The activity of alpha-GLUC was inversely correlated with ROS generation after 12-myristate, 13-acetate phorbol ester stimulation (r=-0.27, n=104), and both alpha-GLUC activity and total output were inversely correlated with the concentration of peroxidase-positive white blood cells among samples with > or =1x10(6)/ml of these cells (r=-0.30 and -0.19, n=165). It is concluded that simple photometric measurement of alpha-GLUC activity in seminal plasma reflects the functional state of the epididymis and may be helpful for the differential diagnosis of certain cases with azoospermia.
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PMID:Seminal plasma alpha-glucosidase activity and male infertility. 957 18


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