Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mild, generalized myopathy (glycogenosis type II) of a 23-year-old male, previously thought to have progressive muscular dystrophy, was studied clinically, electro-myographically, biochemically and with light- and electron microscopes. However, the history and clinical aspects, as well as the registration of high frequency discharges in the electromyogram first made the diagnosis uncertain. This kind of spontaneous activity has been found in nearly all cases reported in the literature. Light microscopic and histochemical examinations show vacular degeneration and glycogen storage in muscle fibres. With the electron microscope we found free dispersed glycogen in the cytoplasm and membrane-bound glycogen, glycogen-filled lysosomes. Biochemical measurements of the muscle enzymes, involved in the glycogen breakdown, were normal except for acid alpha-1,4-glucosidase, which was deficient. The evidence of these findings in this abortive form of glycogenosis type II is discussed and compared with the few cases found in the literature.
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PMID:The symptomatology, morphology and biochemistry of glycogenosis type II (Pompe) in the adult. 5 76

Lactase and maltase, the predominant sugar hydrolases associated with the intestinal brush bordermembrane of the suckling rat, were purified essentially free of the other to near homogeneity (lactase at specific activity 23, maltase at specific activity 58), and their specific physiocochemical properties determined. Antisera prepared to each showed by immunodiffusion a single common precipitin line with pure enzyme and solubilized proteins of the brush border membrane. Brush border membranes were purified 26--35-fold from infant rat intestine. Membranes prepared from 10-day-old rats contained 32% protein, 43% lipid and 25% carbohydrate with lactase and maltase estimated to comprise in excess of 10% and 2%, respectively, of the membrane protein. Immunotitration curves of lactase and maltase showed equivalent antibody binding by the membrane-bound and free enzyme forms. Furthermore, antibody binding to one enzyme did not affect the immunotitration curve or the extractability (by papain or Triton X-100) of the other membrane-bound enzyme. It was concluded that the lactase and maltase molecules are attached singly on the external membrane surface in a spatially independent manner with their antigenic sites as freely available to antibody binding as exhibited by their papain-solubilized counterparts.
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PMID:Sugar hydrolases of the infant rat intestine and their arrangement of the brush border membrane. 11 Mar 47

The arrangement of the sugar hydrolases, sucrase-isomaltase, maltase, and lactase on the microvillus membrane of rat intestine was investigated by immunological technique. The enzymes were purified essentially free of each other to near homogeneity and antisera of high specificity were obtained against each. Microvillus membranes were prepared routinely in high purity from rat intestine and contained an average 61% protein, 20% lipid, and 19% carbohydrate, with the sugar hydrolases comprising an estimated 20--25% of the membrane protein. The immunoreactivity of membrane-bound sucrase-isomaltase, maltase, and lactase was investigated with antisera demostrating specific reactivity to each, when tested in the presence of other membrane extractives. The membrane-bound enzymes were found in each case to combine with antibody in amounts equivalent to that required to effect precipitation of comparable units of the free enzymes from solution. Preloading membrane vesicles with antibodies to any two of the enzymes did not affect either the immunoreactivity or extractability (by papain or Triton X-100) of the third. The antibody-binding studies indicated an arrangement of these enzymes independent of each other on the membrane surface, in a manner allowing each to maintain a high degree of molecular freedom.
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PMID:Sugar hydrolases and their arrangement on the rat intestinal microvillus membrane. 11 6

The organism Bacillus amyloliquefaciens is capable of producing alpha-amylase (1,4-alpha-D-glucan glucanohydrolase, EC 3.2.1.1) and isoamylase (glycogen 6-glucanohydrolase, EC 3.2.1.68) extracellurlarly and a membrane-bound, intracellular alpha-glucosidase (alpha-D-glucoside glucohydrolase, EC 3.2.1.20). The amounts of alpha-glucosidase in cells of B. amyloliquefaciens grown on amylaceous polysaccharides were significantly higher then in cells grown on non-carbohydrate carbon sources. alpha-Glucosidase was exclusively found associated with membranes from ruptured spheroplasts by subcellular fractionation and solubilization studies. Salt solutions and chelating agents alone did not dislodge alpha-glucosidase from membranes, but in combination with detergents were most effective in solubilizing active enzyme (0.1% sodium cholate (pH 8.0)/0.4 M sodium chloride). Purified alpha-glucosidase very rapidly hydrolized p-nitrophenyl alpha-D-glucopyranoside and sucrose. Maltose, maltotriose, isomaltose and isomaltotriose were hydrolized at slower rates, whereas beta-glucosides and polymeric alpha-glucans were not attacked. Other properties of the purified enzyme were as follows: Temperature optimum for catalysis = 39 +/- 1 degrees C; pH optimum = 6.8; molecular weight = 27,000 +/- 1000. alpha-Glucosidase is proposed to function in the endogenous metabolism of alpha-glucans provided extracellularly as carbon sources for growth of B. amyloliquefaciens.
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PMID:alpha-Glucosidase, a membrane-bound enzyme of alpha-glucan metabolism in Bacillus amyloliquefaciens. Purification and partial characterization. 33 55

The activity of the membrane-bound enzymes of the microvillous zone of the entreocytes (maltase, sucrase, trehalase, lactase, cellobiase, alkaline phosphatase and leucylaminopeptidase) was studied in mucosal smears from the proximal jejunum, ileum, caecum and sigmoid flexure in a group of control (C) (8) and germ-free (GF) (7) rabbits. The trypsin and chymotrypsin activity of the contents of the ileum, caecum and sigmoid flexure was studied in 6 C, 5 GF and 5 monocontaminated (MC) rabbits. In summing up it can be stated that the individual membrane-bound enzymes have a different gradient in the various intestinal segments of C and GF rabbits and that they differ reciprocally in character. The maximum statistically significant differences between GF and C rabbits were found in the ileum; in the jejunum they were somewhat smaller and in the caecum smaller still (in this localization the difference was C versus GF). Striking differences in the proportion of the individual disaccharidases were found inthe jejunum and ileum of C rabbits compared with GF rabbits, in which, in both these segments of small intestine the relationship maltase greater than sucrase greater than trehalase greater than lactase was preserved. The proteolytic activity of the intestinal contents likewise had a different gradient character in C, MC and GF rabbits. The maximum activities (especially trypsin) were found in MC animals. The microbial flora is one of the factors regulating the enzymatic activities of the microvillous zone of the enterocytes and it also significantly influences the proteolytic activity of the intestinal contents. This influence is particularly marked in the distal part of the alimentary tube.
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PMID:Digestive enzymes of the mucosa of the small intestine and trypsin and chymotrypsin proteolytic activity of the intestinal contents of germ-free, monocontaminated and conventional rabbits. 35 55

1. The proteins of the intestinal microvillus membrane have been studied during post-natal development in the rat (days 12--37). 2. In suckling animals (up to age 20 days), the majority of alkaline phosphatase, glucoamylase and lactase activities in the distal half of the intestine were located in the supernatant fraction (100000 X g, 60 min). These enzymes were attached to the membrane from the proximal intestine at all ages. 3. Alkaline phosphatase, maltase and lactase activities in the supernatant fractions chromatographed in Sephadex G-200 in positions similar to the corresponding membrane enzyme. Corresponding activities for lysosomal counter-parts of maltase and lactase present in the supernatant fraction chromatographed differently. Moreover, pH optimum of the soluble enzymes was 9.2 for phosphatase and 5.5--6.0 for glycoamylase and lactase. The soluble lactase and alkaline phosphatase were inhibited minimally by p-chloromercuribenzoate, and sodium fluoride respectively. L-Phenylalanine (20 mM) did inhibit the soluble phosphatase by 90%. Thus, the soluble enzymes are not mainly of the lysosomal origin, but have characteristics of membrane-bound enzymes. 4. Polyacrylamide gel electrophoresis in sodium dodecyl sulfate revealed 18 protein bands which were present in adult membranes. Two other proteins were unique for membranes of distal intestine in suckling rats. The proteins corresponding to known enzyme activity changed as expected with age (e.g. sucrase, maltase increased, lactase decreased). Most of the other proteins were also altered in amount during development. Thus, the changes in the microvillus membrane during development in the rat are not limited to specific enzymes.
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PMID:Development of intestinal brush border membrane proteins in the rat. 41 9

Tissues of rats with adjuvant arthritis manifested differences in activity and distribution between free, latent and membrane-bound forms of acid catepsins, alpha-D- and beta-D-galactosidases, alpha-D- and beta-D-glucosidases, beta-D-glucorunidase, hyaluronidase, acid phosphatase, arylsulphatases (A+B). Activation of certain hydrolytic enzymes is observed in tissues of the liver, kidneys, heart and spleen: a rise in total activity (of arylsulphatase in the liver and acid catepsins in the spleen; hyaluronidase in the kidneys, beta-D-glucuronidase in the heart) and a change in the ratio of different forms with a simultaneous increase in the activity of free form (of hyaluronidase in the spleen, acid phosphatase in the heart and liver). Inhibition of alpha-D-glucosidase in the liver and beta-D-glucosidase in the spleen is also detected. A decrease in the activity of beta-D-glucuronidase in the spleen is pronounced in a significant decrease in the activity of each enzyme free form with no changes in the total activity.
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PMID:[Hydrolytic enzymes of rat tissues with adjuvant arthritis]. 72 90

About 90% of the protein of hamster intestinal brush borders was solubilised in 0.25% (w/v) sodium dodecyl sulphate without total loss of biological activity. Detergent-polyacrylamide gel electrophoresis of the solubilised proteins separated 10-15 bands and partially resolved maltase, lactase, sucrase-maltase, trehalase and alkaline phosphatase activities. The disaccharidases, which were associated with the higher molecular weight proteins, were preferentially solubilised with 0.1%. (w/v) Triton X-100, butanol or papain, whereas Tris and NaI extracted only the lower molecular weight proteins, possible derived from the core filaments. Electrophoresis of brush border proteins metabolically labelled with [14-C] glucosamine suggested that many of the membrane-bound enzymes are glycoproteins. However, chromatography of a papain digest on Sephadex G-200 showed that the sucrase-maltase complex can be separated nearly free of carbohydrate without total loss of activity. The importance of characterizing membrane proteins solubilised by a number of techniques is discussed.
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PMID:Solubilization of brush borders of hamster small intestine and fractionation of some of the components. 113 70

Ascorbic acid 2-O-alpha-glucoside (AA-2G) has been reported to have antiscorbutic activity in guinea pigs. The present experiments examined the metabolic fate of AA-2G following ingestion. Oral administration of AA-2G (96 mg) to guinea pigs resulted in a remarkable increase of ascorbic acid in various tissues as well as plasma, but intact AA-2G was detected only in plasma, but intact AA-2G was detected only in plasma and urine in small amounts. The absorption efficiency of AA-2G and ascorbic acid was further determined by using everted gut sacs of rats. Ascorbic acid released from AA-2G on the mucosal side was effectively taken up across intestinal membranes into the serosal side, whereas AA-2G poorly permeated via a passive transport system. The hydrolysis of AA-2G on the mucosal surface of everted gut was completely inhibited by an alpha-glucosidase inhibitor and the hydrolytic activity of a crude membrane extract diminished to one-forth after immunoprecipitation with the antibody specific to maltase. From these results, it is concluded that ingested AA-2G serves as a vitamin C source through the hydrolysis by intestinal membrane-bound alpha-glucosidase, mainly maltase, and the subsequent absorption of released ascorbic acid.
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PMID:Evaluation of ascorbic acid 2-O-alpha-glucoside as vitamin C source: mode of intestinal hydrolysis and absorption following oral administration. 129 35

The antiprotozoal drug metronidazole, when administered orally at a dose level of 100 mg/kg body wt. daily for 7 days to rats, brought about significant elevation of renal brush-border-membrane-bound hydrolytic enzymes, such as alkaline phosphatase, maltase, sucrase, and leucine aminopeptidase (LAP). Kinetic analysis of the enzymes (substrate saturation) indicated that the drug produced an increase in the maximum of apparent initial enzyme velocity (Vmax), while the substrate affinity constant (Km) remained unaltered. These changes were not recovered to the normal level even after the drug regimen was stopped and the animals were allowed to recover for a period of 7 days. Lipid analysis of brush border membrane (BBM) revealed a significant elevation in the cholesterol, phospholipid, and ganglioside levels, while no marked change was recorded in triglyceride, free fatty acid and plasmalogen. Study of the temperature-dependent parameters of the enzymes showed that metronidazole induced a shift in the transition temperature (To) in LAP with nearly total reversibility in the recovery group. No such change was seen in the other enzymes. However, there also was a lowering in the energy of activation (Ea) below To, which returned to normal after the treatment was withdrawn.
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PMID:Changes in membrane-bound hydrolases by metronidazole in rat renal brush border. 141 Aug 3


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