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)

(1) A simple method is described for the isolation of the lysosomal enzyme, acid alpha-glucosidase (alpha-D-glucoside glucohydrolase, EC 3.2.1.20) from normal human liver. Antibodies raised against the purified enzyme were immobilized by covalent coupling to Sepharose 4B. (2) Acid alpha-glucosidase can be quantitatively removed from normal urine by incubating with an excess of immobilized antibody. With p-nitrophenyl-alpha-glucoside as substrate, acid alpha-glucosidase accounts for 91 +/- 3% of the total alpha-glucosidase activity at pH 4.0 IN Normal urine. (3) In urine from a patient with the infantile form of Pompe's disease ('acid maltase deficiency'), no alpha-glucosidase activity could be removed by the immobilized antibody, in agreement with the fact that acid alpha-glucosidase is absent in these patients. (4) In urine from patients with the late-onset form of Pompe's disease, 46 +/- 11% of the alpha-glucosidase activity at pH 4.0 can be removed by incubation with immobilized antibodies, indicating that residual acid alpha-glucosidase activity is present in urine of these patients. The residual acid alpha-glucosidase activity amounts to about 5% of that in the urine of control persons. (5) If acid alpha-glucosidase is adsorbed to immobilized antibodies, the activity can still be measured with p-nitrophenyl-alpha-glucoside as substrate. The Km for p-nitrophenyl-alpha-glucoside is not significantly changed by adsorbing purified acid alpha-glucosidase to immobilized antibodies. (6) The properties of acid alpha-glucosidase from urine of patients with late-onset Pompe's disease were compared with those of acid alpha-glucosidase from normal urine, both adsorbed to immobilized antiserum. The pH-activity profile of the enzyme from urine of patients with late-onset Pompe's disease can not be distinguished from that of the normal urinary enzyme. The Km for p-nitro-phenyl-alpha-glucoside of the two enzymes is identical, both at pH 4 and 3. The titration curves of the two enzymes with immobilized antibodies are identical.
 ...
PMID:Use of immobilized antibodies in investigating acid alpha-glucosidase in urine in relation to Pompe's disease. 3 57

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.
 ...
PMID:The symptomatology, morphology and biochemistry of glycogenosis type II (Pompe) in the adult. 5 76

Prenatal diagnosis of type 2 glycogenosis (Pompe's disease) has been done on cultured amniotic fluid cells, using a semi-automated fluorimetric kinetic assay for alpha-D-glucosidase with 4-methylumbelliferyl-alpha-D-glucoside as substrate. The activity of the enzyme was related to that of beta-D-galactosidase, and found to be absent in cells from an affected fetus. The diagnosis was confirmed in fetal liver, where the same assay was used to show absence of alpha-D-glucosidase activity with normal beta-D-galactosidase activity, and where increased glycogen deposition was demonstrated histologically. This type of assay is generally applicable to lysosomal enzymes, and to other fluorigenic enzyme reactions.
 ...
PMID:A sensitive semi-automated kinetic assay of alpha-D-glucosidase for the prenatal diagnosis of type 2 glycogenosis (Pompe's disease). 11 83

The clinical, biochemical, morphological and electrophysiological findings in a 13-month-old child, who died of glycogenosis type II, is presented. In addition to the deficiency of alpha-1,4-glucosidase, which is typical for the disease, a deficiency in hyaluronidase could be detected for the first time in the skeletal and heart muscles and in the liver. On the other hand, the beta-glucoronidase and beta-acetylglucosaminidase activity was highly increased. Deposits of a substance, most probably an acid mucopolysaccharide, which could be differentiated from glycogen by chromography and electronmicroscopy, could be detected in the muscle. A pathogenetical connection with the hyaluronidase defect is imminent.
 ...
PMID:[Clinical, biochemical, morphological and electrophysiological studies of glycogenosis Type II in childhood with double deficiency of enzymes (author's transl)]. 12 55

Extensive 'vacuolization' could be demonstrated in nearly all plasma cells and in some lymphocytes of an adult with glycogenosis type II (Pompe's disease). The biochemically defined diagnosis acid maltase deficiency (AMD) could be ascertained by examination of the maltase activity of the patient's leukocytes. Electron microscopical, microspectrographic, and cytochemical investigations revealed electron dense inclusions, which show an UV absorption at 276 nm and a positive reaction after PAS staining of plastic embedded material. Since no other abnormalities of the plasma cells could be found, our results are presumably indicative for a connection of AMD and a glycoprotein storage in the plasma cells of the patient.
 ...
PMID:New kind of cytoplasmic inclusions of plasma cells in acid maltase deficiency. 16 54

Residual acid maltase activity was found by a sensitive fluorometric assay in muscle biopsies from 15 patients with late-onset acid maltase deficiency (mean, 6.91 percent; range, 2.4 to 12.2) but not in biopsy or autopsy muscle from three patients with the infantile form. Electrophoresis, kinetic characteristics, and subcellular fractionation indicated that the residual activity was lysosomal acid maltase and not a contaminating isozyme of neutral maltase. There was no correlation between the amount of residual acid maltase activity and the severity of the clinical picture or glycogen accumulation. The presence of acid maltase activity in muscle, liver, and, to a greater extent, leukocytes in late-onset but not infantile acid maltase deficiency and the failure of the two disease forms to occur in the same family suggest that they are genetically distinct.
 ...
PMID:Residual acid maltase activity in late-onset acid maltase deficiency. 26 6

Leptomeres, the laminated structures consisting of bundles of very fine filaments separated into bands about 260 nm wide by periodic transverse dense lines 20--80 nm wide, were observed frequently in cultured muscle fibers of 8 patients with acid maltase deficiency, 4 with sporadic, adult-onset idiopathic "autophagic" vacuolar myopathy (that is not acid-maltase deficient) and one with abnormal mitochondria, but in only one of greater than 50 other cultures of normal and denervated human muscle. They were also induced abundantly in cultured normal human muscle by exposure to 0.5 mM DNP.
 ...
PMID:Leptomeres in cultured human muscle. 35 7

alpha-Glucosidase activity was assayed in polymorphonuclear cells and lymphocytes from human peripheral blood with 4-methylumbelliferyl-alpha-D-glucopyranoside as substrate in the presence of sodium taurocholate. The pH vs. activity curve of the alpha-glucosidase indicated that differential estimation between acid and neutral alpha-glucosidases was difficult to perform with polymorphonuclear cells, but easily accessible with lymphocytes. The use of peripheral blood lymphocytes for the enzymatic diagnosis of Pompe's disease seemed to be more reliable than the use of whole leucocytes; this also the case with a classical Pompe's patient. The lymphocytes from the parents had normal or low normal activity of acid alpha-glucosidase in the freshly isolated state, but when cultured with phytohaemagglutinin for 72 h, the stimulated lymphocytes of both parents showed about half the enzyme activity of the cultured controls. It was deemed possible in all probability to identify the carrier state by assay of the enzyme activity in phytohaemagglutinin-stimulated lymphocytes.
 ...
PMID:alpha-glucosidase activity in human leucocytes: choice of lymphocytes for the diagnosis of Pompe's disease and the carrier state. 36 Dec 94

We used a double labeling technique to search for molecular defects in two fibroblast strains obtained from patients with Pompe's disease. Analysis of the double labeled subcellular fractions by sodium dodecyl sulfate (SDS) electrophoresis did not reveal any abnormalities except in the "mitochondrial-lysosomal" fraction. In this fraction ratio deviations indicated that in Pompe's disease there was a significant decrease in counts of a protein with molecular weight of about 29,000. After solubilization by freeze-thawing this protein was shown to have an isoelectric point of 7.9 in contrast to the alpha-glucosidase which focused at about pH 4.7. Two-stage gel studies demonstrated an estimated 90% reduction of this protein in Pompe's disease. Two-stage studies of acid alpha-glucosidase did not show any abnormal ratios of leucine incorporation. Similar although quantitatively less pronounced results were obtained in the study of skin fibroblasts from a patient with adult glycogen storage disease type II.
 ...
PMID:Searching for molecular abnormalities in genetic diseases by the use of a double labeling technique. II. Deficiency of a basic protein in fibroblasts of patients with Pompe's disease. 36 58

In a postmortem study of a patient with adult-onset acid maltase deficiency (AMD), morphological abnormalities were confined to skeletal muscle and consisted of a vacuolar myopathy. Acid maltase activity, however, was approximately 6% of normal in muscle, liver, and brain, and 3% of normal in heart. Kinetic characteristics, and inhibition by antibodies and Zn++, showed that the residual activity was "authentic" acid maltase. Neutral maltase activity was normal in muscle and liver, but decreased in brain (55% of normal) and heart (19% of normal). Although the relative decrease of acid maltase was similar in different tissues, absolute residual activity was lowest in skeletal muscle: this may explain the selective involvement of this tissue in late-onset AMD.
 ...
PMID:Adult-onset acid maltase deficiency: a postmortem study. 37 69


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>