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 initial step of disaccharide dissimilation by Actinomyces viscosus serotype 2 strain M-100 was studied. Sucrase activity was found in the 3,000 X g particulate fraction and the 37,000 X g soluble fraction of the cells, whereas lactase activity was found almost exclusively in the 37,000 X g soluble fraction. Neither sucrase nor lactase activity was appreciable in the culture liquor. Sucrose phosphorylase, alpha-glucosidase, and polysaccharide synthesis activities were not observed in the soluble cell fraction. The sucrase was identified as invertase (EC 3.2.1.26; beta-D-fructofuranoside fructohydrolase). The lactase was identified as beta-galactosidase (EC 3.2.1.23; beta-D-galactoside galactohydrolase). The enzymes in the 37,000 X g soluble fraction were separable by diethylamino-ethyl-cellulose chromatography, giving one beta-galactosidase peak and one major and one minor invertase peak. Acrylamide gel electrophoresis showed different electrophoretic mobilities of the enzymes. The molecular weight of the beta-galactosidase is about 4.2 X 10(5) and that of invertase is about 8.6 X 10(4). The beta-galactosidase has a Km for lactose of about 6 mM and a pH optimum between pH 6.0 and 6.5. The major invertase component has a Km for sucrose of about 71 mM and a pH optimum between pH 5.8 and 6.3.
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PMID:Identification, separation, and preliminary characterization of invertase and beta-galactosidase in Actinomyces viscosus. 1 74

The influences of phenobarbital (PB) on enzymes of the carbohydrate metabolism in rat liver are examined during pre- and postnatal development. The following results are obtained: (1) PB generally increases G-6-Pase before and after birth. (2) Both the active and the inactive forms of phosphorylase are increased significantly during the prenatal periods. During the postnatal periods, mainly the active form of phosphorylase is influenced by PB. (3) Total glycogen synthetase is increased by PB during prenatal development but decreased during postnatal development. (4) The activity of alpha-glucosidase is increased during the prenatal period. (5) The activity of F-6-PK and 6-PGDH are decreased during the prenatal periods and G-6-PDH activity is decreased during both pre- and postnatal periods.
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PMID:The influence of phenobarbital on carbohydrate metabolism in developing rat liver. 18 Dec 54

During meiosis in Saccharomyces cerevisiae, the polysaccharide glycogen is first synthesized and then degraded during the period of spore maturation. We have detected, in sporulating yeast strains, an enzyme activity which is responsible for the glycogen catabolism. The activity was absent in vegetative cells, appeared coincidently with the beginning of glycogenolysis and the appearance of mature ascospores, and increased progressively until spourlation was complete. The specific activity of glycogenolytic enzymes in the intact ascus was about threefold higher than in isolated spores. The glycogenolysis was not due to combinations of phosphorylase plus phosphatase or amylase plus maltase. Nonsporulating cells exhibited litle or no glycogen catabolism and contained only traces of glycogenolytic enzyme, suggesting that the activity is sporulation specific. The partially purified enzyme preparation degraded amylose and glycogen, releasing glucose as the only low-molecular-weight product. Maltotriose was rapidly hydrolyzed; maltose was less susceptible. Alpha-methyl-D-glucoside, isomaltose, and linear alpha-1,6-linked dextran were not attacked. However, the enzyme hydrolyzed alpha-1,6-glucosyl-Schardinger dextrin and increased the beta-amylolysis of beta-amylase-limit dextrin. Thus, the preparation contains alpha-1,4- and alpha-1,6-glucosidase activities. Sephadex G-150 chromatography partially resolved the enzyme into two activities, one of which may be a glucamylase and the other a debranching enzyme.
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PMID:Glycogenolytic enzymes in sporulating yeast. 35 Aug 52

Each of 12 types of glycogen storage disease (GSD O-XI) is delineated by clinical, biochemical and histologic features that allow its identification in future patients. GSD II occurs in 2 forms that are not both encountered in the same family. GSD IIa is the infantile fatal form with cardiomegaly, increased cardiac glycogen concentration and cardiac failure; GSD IIb is the adult form with clinically normal heart and normal cardiac glycogen concentration. Nonetheless, the heart muscle of both forms is equally deficient in acid alpha-glucosidase activity, and this raises questions as to the latter's role in the pathophysiology of GSD II. The appearance of hepatocytes in GSD IIa becomes normal after the administration of alpha-glucosidase. Using electron microscopy of uncultured amniotic fluid cells, the prenatal diagnosis of GSD IIa is feasible within one day after the amniocentesis. GSD VI and IX are instances of benign hepatomegaly except when GSD IX and III occur in the same child; one such patient died suddenly at home. There are 2 modes of inheritance in GSD IX: one (GSD IXa) is autosomal recessive, the other one (GSD IXb) is X-linked recessive. In either form the Km of the remaining liver phosphorylase kinase is normal. Both forms of GSD IX have the normal blood sugar response to glucagon, whereas GSD VI does not. Equally, the glucagon tolerance curve is flat in GSD XI although in vitro activity of glycolytic enzymes is normal. The in vivo administration of glucagon in GSD XI is followed by the normal increase of both urinary 3'5'-AMP and hepatic phosphorylase activity. GSD V may have increased activity of muscle phosphorylase kinase. Deficiencies of debrancher, liver phosphorylase and liver phosphorylase kinase can occur singly or in combination. Before any novel treatment of GSD is initiated, one should obtain tissue for the biochemical determination of the exact type of GSD. This is so because the clinical signs may not indicate the type with the necessary precision, and because some types are compatible with normal life and thus may not require therapy, especially if the latter is unproved and potentially dangerous.
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PMID:Glycogen storage diseases. 78 7

Activities of gamma-amylase (acidic alpha-glucosidase) and phosphorylase were studied in brain of normal rabbits and in animals subjected to craniocerebral trauma. The gamma-amylase activity was slightly increased within 10 min after the trauma and its was decreased within 24 hrs. The phosphorylase activity was decreased in the both periods of investigation. Administration of strychnine into normal animals increased the gamma-amylase activity and decreased the phosphorylase activity. At the same time, the normalization of the gamma-amylase activity was observed after stimulation of the central nervous system (by phenamine) of traumatized animals. Inhibition of the central nervous system of traumatized animals (by administration of urethane and barbital mixture) led to the subsequent decrease of the gamma-amylase activity (in several cases up to the zero value) without any alterations in the phosphorylase activity. Participation of gamma-amylase in glycogen metabolism of rabbit brain is discussed.
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PMID:[Glycogen degradation in rabbit brain under normal conditions and following cranio-cerebral injury]. 88 61

Glycogen can be degraded in mammalian tissues by one of three isozymes of glycogen phosphorylase, termed muscle (M), liver (L) and brain (B) after the tissues in which they are preferentially expressed in adult animals, or by members of the family of alpha-glucosidases. In the current study, we have examined the developmental expression of these enzymes and their respective mRNAs in rabbit tissues, with particular emphasis on the developing lung, a tissue in which glycogen serves as an important source of carbon for surfactant phospholipid biosynthesis. Native gel activity assays and RNA blot hybridization analysis revealed that the B isoform of glycogen phosphorylase predominates in fetal and adult lung tissues, accompanied by a low level of expression of the M isoform. Total B and M phosphorylase activities increased during fetal lung development, with a peak at day 28 of gestation, then decreased to the adult level at term. This peak in activity coincided with the peak period of glycogen degradation in developing lung. While the increase in M isozyme activity was correlated with an increase in the level of its mRNA, B isoform mRNA showed no significant alteration during development, suggesting that the increase in B isoform activity is determined by a posttranscriptional mechanism. Analysis of phosphorylase mRNA levels in developing liver, skeletal muscle, brain and heart revealed a diverse expression pattern. The L isozyme mRNA was predominant at all time points in liver, the M isozyme was predominant at all time points in muscle, the B isozyme was predominant at all time points in brain, and heart contained a mixture of B and M mRNA in roughly equal ratios at all time points. Thus, our studies of phosphorylase mRNA in the rabbit provide no evidence for general predominance of the B isozyme in fetal tissues, or for isozyme 'switching' from the B to the L or M forms during development, as has been suggested by others. In addition to the increase in phosphorylase activity, acid, but not neutral alpha-glucosidase activity was found to increase significantly during fetal lung development, again with a peak at day 28 of gestation. Interestingly, RNA blot hybridization analysis with a probe for lysosomal alpha-glucosidase revealed no change in the level of expression of its 4 kb transcript in developing lung. Instead, we observed induction of a structurally related mRNA of 7.4 kb that peaked at day 28 of gestation. Hybridization with a sucrase/isomaltase-specific oligonucleotide excluded the possibility that the 7.4 kb transcript encodes this protein.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Developmental expression of glycogenolytic enzymes in rabbit tissues: possible relationship to fetal lung maturation. 195 55

Rats trained on a diurnal controlled meal-feeding schedule and injected with a single dose of 3,5,3'-triiodothyronine (T3) failed to accumulate liver glycogen and incorporated less D-[6-3H]glucose into glycogen than normally observed during the feeding period. In the experimental group, the concentration of liver adenosine 3',5'-cyclic monophosphate (cAMP) did not fall during feeding and the pattern of activities of glycogen phosphorylase, glycogen synthase, and phosphorylase kinase remained conductive to glycogenolysis. Liver lysosomal alpha-glucosidase activity normally fell during feeding periods. After T3 treatment the activities of alpha-glucosidase and two lysosomal cathepsins (B1 and D) were elevated. The evidence suggests that T3 may induce both liver phosphorylase kinase and lysosomal alpha-glucosidase. This outcome of T3 excess, in concert with previously described T3-inducible systems, provides a plausible explanation for the failure of glycogen accumulation in this experimental model.
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PMID:Mechanisms underlying enhanced glycogenolysis in livers of 3,5,3'-triiodothyronine-treated rats. 210 55

A case of 25-year-old woman with glycogen storage myopathy is reported here. She was hospitalized for acute heart failure after alcohol drinking. The electrocardiogram on admission showed marked ST elevation. Laboratory data showed elevated levels of serum myogenic enzymes but no rise in cardiomyogenic enzyme: CK 3862 IU/l CK-MB 35 IU/l, LDH 427 IU/l, GOT 203 IU/l. After several days, she recovered from acute heart failure and could walk without supporting. ST elevation in ECG and elevated myogenic enzymes were also normalized. The occurrence of acute myocardial infarction was ruled out because a coronary angiogram and 99 Tcm scintigram were normal. Physical examination revealed proximal muscular weakness and mental retardation (WAIS, total 72). Venous lactate response was normal after semi-ischemic forearm exercise. PAS staining of muscle specimen showed an excess deposit of glycogen. Ragged-red fibers were not seen on Gomori-trichrome stain. By electron microscopy, a large amount of glycogen particles were demonstrated in the subsarcolemma, but there were no abnormal mitochondrial changes. Biochemical analysis showed accumulation of glycogen in muscles: 28.7 mg/g muscle (normal 11.4 +/- 4.2 mg/g muscle). The activities of enzyme in the pathway of glycogen and glycogenosis (alpha-glucosidase, amylo-1,6-glucosidase, phosphorylase a, phosphorylase kinase, phosphofructokinase, etc.) were within normal limits. The spectrum of glycogen iodine complex was normal. Our case was different from any type of muscle glycogen storage disease previously reported. The etiology of an excess of glycogen deposit in muscles is unknown.
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PMID:[A case of glycogen storage myopathy with acute heart failure]. 220 34

1. Glycogen, glucose, lactate and glycogen phosphorylase concentrations and the activities of glycogen phosphorylase a and acid 1,4-alpha-glucosidase were measured at various times up to 120 min after death in the liver and skeletal muscle of Wistar and gsd/gsd (phosphorylase b kinase deficient) rats and Wistar rats treated with the acid alpha-glucosidase inhibitor acarbose. 2. In all tissues glycogen was degraded rapidly and was accompanied by an increase in tissue glucose and lactate concentrations and a lowering of tissue pH. In the liver of Wistar and acarbose-treated Wistar rats and in the skeletal muscle of all rats glycogen loss proceeded initially very rapidly before slowing. In the gsd/gsd rat liver glycogenolysis proceeded at a linear rate throughout the incubation period. Over 120 min 60, 20 and 50% of the hepatic glycogen store was degraded in the livers of Wistar, gsd/gsd and acarbose-treated Wistar rats, respectively. All 3 types of rat degraded skeletal muscle glycogen at the same rate and to the same extent (82% degraded over 2 hr). 3. In Wistar rat liver and skeletal muscle glycogen phosphorylase was activated soon after death and the activity of phosphorylase a remained well above the zero-time level at all later time points, even when the rate of glycogenolysis had slowed significantly. Liver and skeletal muscle acid alpha-glucosidase activities were unchanged after death. 4. The decreased rate and extent of hepatic glycogenolysis in both the gsd/gsd and acarbose-treated rats suggests that this process is a combination of phosphorolysis and hydrolysis. 5. Glycogen was purified from Wistar liver and skeletal muscle at various times post mortem and its structure investigated. Fine structural analysis revealed progressive shortening of the outer chains of the glycogen from both tissues, indicative of random, lysosomal hydrolysis. Analysis of molecular weight distributions showed inhomogeneity in the glycogen loss; in both tissues high molecular weight glycogen was preferentially degraded. This material is concentrated in lysosomes of both skeletal muscle and liver. These results are consistent with a role for lysosomal hydrolysis in glycogen degradation.
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PMID:Post mortem glycogenolysis is a combination of phosphorolysis and hydrolysis. 227 18

The changes in the activities of three important glycogen metabolising enzymes, viz. glycogen synthetase, glycogen phosphorylase and alpha-D-glucosidase, along with glycogen content have been measured in adult human heart and human fetal heart collected at 13-36 weeks of gestation. At an early period, particularly 13-16 weeks of gestational age, the activity of glycogen synthetase and glycogen content were found to be maximum. However the activity of glycogen phosphorylase remained constant throughout the gestation and that of alpha-D-glucosidase showed a peak at 25-28 weeks of gestation, thereby indicating that fetal heart tissue has the capacity to utilise glycogen for energy.
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PMID:Age-related changes of glycogen metabolism in human fetal heart. 277 20


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