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)

Tissues from the cerebral cortex, liver and myocardium of a patient with Lafora disease were obtained at autopsy and were studied biochemically. 1. Glucose content in the myocardium and liver was almost nil while that in the controls was 0.66 mg/g wet weight in the former and 8.80 mg/g wet weight in the latter. Glycogen content in the cerebral cortex and myocardium was about 10 and 3 times more than in controls. 2. Polyglucosan extracted from the cerebral cortex, liver and myocardium had a longer exterior glucose chain than that in the liver of the control but a normal, alpha or beta 1,4-glucosidic linkage was observed. 3. The activities of glucose-6-phosphatase and amylo-1,6-glucosidase in the cerebral cortex, liver and myocardium were well preserved. The activities of acid maltase in the three organs mentioned above and of neutral maltase in the myocardium were elevated twice and one and half times more than the control. Phosphorylase levels in the myocardium were extremely small, while in the cerebral cortex and liver normal activities were observed. In light of these findings, glycogen metabolism in Lafora disease is discussed.
 ...
PMID:Biochemical studies on tissues from a patient with Lafora disease. 17 19

Glycogen supercompensation (increase in muscle glycogen content above basal) is an established phenomenon induced by unknown mechanisms. It consists of both insulin-dependent and -independent components. Here, we investigate insulin-independent glycogen supercompensation in isolated, intact extensor digitorum longus muscles from mice. Muscles were stimulated electrically, incubated in vitro with 5.5 mM glucose for up to 16 h and then analysed for glycogen, glucose uptake and enzyme activities. Basal glycogen was 84+/-6 micro mol glucosyl units/g dry muscle and was depleted by 80% after 10 min contraction. Glycogen increased after contraction, reaching a peak value of 113+/-9 micro mol glucosyl units/g dry muscle ( P<0.05 vs. basal) by 6 h, and returned to basal values by 16 h (84+/-8). Maximal activities of glycogen synthase, phosphorylase and alpha-glucosidase were not significantly altered by contraction or during the 6-h recovery period. Glycogen synthase fractional activity (0.17/7.2 mM glucose-6-P; inversely related to phosphorylation state of the enzyme) was increased about twofold early after contraction but then decreased and was slightly lower than baseline during the period of supercompensation (4-6 h). Phosphorylase fractional activity (+/-adenosine monophosphate; directly related to phosphorylation state of the enzyme) decreased to 60% of basal after contraction and decreased further during the initial 4 h of recovery to 40% of basal ( P<0.01 vs. basal). After 4 h recovery, glucose uptake was slightly (50%) higher in the stimulated than in the non-stimulated muscle ( P<0.01). Thus, insulin-independent glycogen supercompensation involves inactivation of phosphorylase and hence an inhibition of glycogen breakdown.
 ...
PMID:Insulin-independent glycogen supercompensation in isolated mouse skeletal muscle: role of phosphorylase inactivation. 1508 41

Chloroplasts isolated from spinach (Spinacia oleracea L., cv. vital(R)) plants grown under controlled light/dark and temperature regimes, contained the phosphorolytic and amylolytic pathways for starch breakdown. The latter consists at least of alpha- and beta-amylase and maltase. Only low amylolytic activity was observed in chloroplasts isolated during the light phase. In chloroplasts prepared during the dark phase, this activity was almost twice as high. These diurnal oscillations of the amylolytic activity were maintained when the plants were kept in prolonged darkness or continuous light. The amylolytic system exhibited a sharp pH optimum between 5.8 and 6.0. Phosphorylase activity, when assayed with saturating concentrations of inorganic phosphate, did not show diurnal fluctuations.
 ...
PMID:Diurnal oscillation of amylolytic activity in spinach chloroplasts. 1666 May 84

As starch is the main seed reserve material in both species of Araucaria of South America, A. araucana and A. angustifolia, it is important to understand starch breakdown in both embryo and megagametophyte tissues of Araucaria seeds. Sugar analysis by thin layer chromatography indicates that sucrose is the main sugar produced in both tissues. Enzyme reactions coupled to benzidine oxidation indicate that sucrose is the main sugar moved from the megagametophyte to the growing regions of the embryo via the cotyledons.Phosphorylase was detected in both embryo and megagametophyte tissues by the formation of [(32)P]glucose-1-P and by formation of [(14)C] amylopectin from [(14)C]glucose-1-P. The enzyme activity increases 5-fold in both embryo and gametophyte to a peak 18 hours after the start of imbibition. Debranching enzyme, alpha-glucosidase, and hexokinase are also present in both embryonic and megagametophytic tissues.Branched glucan oligosaccharides accumulate during this time, reaching a maximum 40 hours after imbibition starts, and decline after germination occurs.The pattern of activity of the enzymes studied in this work suggests that starch degradation is initiated by alpha-amylase and phosphorylase in the embryo and by phosphorylase mainly in the megagametophyte. Sucrose-P synthase seems to be the enzyme responsible for sucrose synthesis in both tissues.
 ...
PMID:Starch Degradation Metabolism towards Sucrose Synthesis in Germinating Araucaria araucana Seeds. 1666 47