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

---

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

The relationship between enzyme activity, cell geometry, and the ploidy levels has been investigated in Saccharomyces cerevisiae. Diploid cells have 1.57 times the volume of haploid cells under nonlimiting growth conditions (minimal medium). However, when diploid cells are grown under conditions of carbon limitation, they have the same volume as haploid cells. Thus, by altering the environmental conditions, cell size can be varied independently of the degree of ploidy. The results indicate that the basic biochemical parameters of the cell are primarily determined by cell geometry rather than ploidy level. RNA content, protein content, and ornithine transcarbamylase (carbamoylphosphate: L-ornithine carbamoyltransferase, EC 2.1.3.3), tryptophan synthetase [L-serine hydro-lyase (adding indole), EC 4.2.1.20], and invertase (alpha-D-glucoside glucohydrolase, Ec 3.2.1.20) activity are related to cell volume, whereas acid phosphatase (orthophosphoric-monoester phosphohydrolase, EC 3.1.3.2) activity, a cell surface enzyme, is related to the surface area of the cells. Fitness is determined by the activity of certain cell surface enzymes, such as acid phosphatase, diploids would be expected to have a lower fitness than haploids because of the lower surface area/volume ratio. However, when fitness is determined by the activity of an internal enzyme, diploids would be expected to have the same fitness as haploids. Results from competition experiments between haploids and diploids are consistent with these predictions. The significance of these results to the evolution of diploidy as the predominant phase of the life cycle of higher plants and animals is discussed.
...
PMID:The relationship between enzyme activity, cell geometry, and fitness in Saccharomyces cerevisiae. 109 69

Streptolysin O was measured in subcellular fractions of group A streptococci obtained after preparation of protoplasts in a hypertonic buffer containing raffinose. Most of the activity was located in the periplasm (the region between cell wall and membrane) and did not differ in several characteristics from that of extracellular streptolysin O. Of the enzymes used as subcellular markers, aldolase and maltase (cytoplasmic) and acid phosphatase (membrane associated) were in the same fractions as found in other bacteria. However, the location of alkaline phosphatase differed from that of other bacteria in the most of the activity was in cytoplasm rather than in the periplasm.
...
PMID:Cellular location of streptolysin O. 110 77

1. Intact parenchymal and non-parenchymal cells were isolated from rat liver. The parenchymal cells were purified by differential centrifugation, while non-parenchymal cells were obtained free of parenchymal cell contamination by preferentially destroying the parenchymal cells with the aid of pronase (0.25%). 2. The ability to isolate pure intact parenchymal and non-parenchymal cells permitted the characterization and measurement of specific activities of various lysosomal enzymes, representing the main functional hydrolytic activities of the lysosomes in these distinct cell types. 3. Lysosomal enzymes catalysing the hydrolysis of the terminal carbohydrate moiety of glycoproteins and glycolipids were not particularly enriched in the non-parenchymal cells as compared to parenchymal cells. The ratio of the specific activities of non-parenchymal cells over parenchymal cells varied between 0.7 for N-acetyl-beta-D-hexoseaminidase to 2.1 for alpha-glucosidase. This suggests no specific role of the non-parenchymal cells in the hydrolysis of terminal carbohydrate moieties of glycoproteins and glycolipids. 4. The enzymes acid phosphatase and aryl sulphatase, representing the phosphate and sulphate hydrolyzing activities, were enriched in the non-paranchymal cells as compared to the parenchymal cells by a factor of 2.5. 5. The most important peptidase cathepsin D, representing protein breakdown capacity, is enriched in the non-parenchymal cells as compared to parenchymal cells by a factor 6.0, suggesting a possible specific function of non-parenchymal cells in protein breakdown. 6. The most enriched lysosomal enzyme, representing lipid hydrolysis, is acid lipase, which is enriched in the non-parenchymal cells with a factor of 10. 7. The distribution of lysosomal enzymes between parenchymal and non-parenchymal cells suggests different functional roles of the lysosomes in these cell types. It can be concluded that the non-parenchymal cells possess a set of lysosomal enzymes which makes them extremely suitable for a phagocytic and antimicrobial function in the liver.
...
PMID:Identity and activities of lysosomal enzymes in parenchymal and non-parenchymal cells from rat liver. 118 30

The total activity of four lysosome enzymes--acid phosphatase, beta-glucuronidase, alpha-glucosidase and beta-N-acetylglucosaminidase--is studied in liver homogenate at 2, 6, 24 and 48 hours after the last meal in rats, previously sustained on a single-daily-feeding regimen. In addition, the free activity (percentage of the total) of the latter enzyme and its activity in the serum as well are investigated. A rise of the total activity of the first three enzymes is recorded within 48 hours after the beginning of starvation. The free activity of beta-N-acetylglucosaminidase shows an increase at 48 hours, while its activity in the serum--as early as 24 hours. The changes described above are interpreted as an expression of lysosome membrane permeability enhancement under fasting conditions.
...
PMID:[Effect of short-term fasting on liver lysosomes in rats, biochemical studies (preliminary report)]. 123 93

Studies have been carried out on activities of lysosomal beta-N-acetylhexosaminidase (hex), beta-galactosidase (beta-gal), alpha-glucosidase (alpha-glu), and acid phosphatase (AP) in serum and urine from patients with juvenile diabetes and matched controls. There is a large increase in blood and urinary hex activity (the former presenting three distinct patterns of abnormality), a moderate increase in urinary beta-gal, and a small increase in urinary alpha-glu activity, but no elevation of blood or urinary AP in the diabetics. Urinary alpha-glu activity in the diabetics shows striking inhibition by glucose, and this may reflect a similar phenomenon in vivo. Although glycohydrolase activities are elevated in patients with no detectable microangiopathy, more striking changes may be observed in patients with severe small-vessel disease. These alterations may be associated with increased glycoprotein catabolism in the diabetic, an area in need of further studies in the human and experimental diabetic animal.
...
PMID:Altered lysosomal glycohydrolase activities in juvenile diabetes mellitus. 126 40

Renal epithelial function, proton flux and sodium stimulated proton flux, was observed in vesicles isolated from the brush border of the proximal tubule of Sockeye Salmon (Oncorhynchus nerka) during migration. Brush border membrane vesicles (BBMV) were isolated from the body kidney of Sockeye Salmon using aggregation/differential centrifugation techniques. Vesicle purity was tested using a series of epithelial and basal lateral markers including alkaline phosphatase, maltase, gamma-glutamyl transferase (GGTP), Mg(2+)-activated ATP-ase, Na(+)+K(+)-activated ATPase, and 5'-nucleotidase and the lysosomal marker acid phosphatase. An enrichment/depletion factor for each marker was determined by comparison of purified BBMV with kidney homogenate. Vesicles exhibit an enrichment factor for alkaline phosphatase, GGTP, maltase, Mg(2+)-activated ATP-ase, Na(+)+K(+)-activated ATPase, and 5'-nucleotidase. A depletion factor was observed for acid phosphatase. Vesicle integrity was tested by measuring the time course of proton flux in the presence of a pH gradient. Amiloride sensitive sodium stimulated proton flux was observed in these vesicles. The presence of sodium caused a saturable increase in the rate of proton flux, indicating the activity of a sodium/proton antiport protein in BBMV.
...
PMID:Proton transport and Na+/H+ exchange in vesicles isolated from sockeye salmon (Oncorhynchus nerka) kidneys during migration from salt to fresh water. 132 4

The ciliated protozoon Tetrahymena thermophila was immobilized for production of secreted lysosomal enzymes in two ways. Cells entrapped in solid Ca-alginate spheres survived but were unable to grow and multiply. However, when encapsulated in hollow Ca-alginate spheres Tetrahymena multiplied well, reaching 0.9 x 10(7) cells/ml. These immobilized cells secreted large amounts of lysosomal enzymes when the medium was changed daily. This system was transferred to a reactor scale using a conical bubble column reactor for semicontinuous cultivation of the encapsulated cells. Under these conditions alpha-glucosidase, beta-glucosidase, beta-hexosaminidase and acid phosphatase were produced for at least 4 weeks. The hollow spheres were stable for 3 months and contained living and secreting Tetrahymena cells during this time. Immobilized T. thermophila cells can thus serve as a good source for production of commercially interesting enzymes.
...
PMID:Lysosomal enzymes produced by immobilized Tetrahymena thermophila. 136 1

The effects of simvastatin 40 mg per day for 14 weeks on the pituitary-testis axis of 19 men with familial hypercholesterolaemia have been examined in a single-blind study. Simvastatin significantly reduced serum low density lipoprotein (LDL) cholesterol and triglycerides by 45% and 30%, respectively, and significantly increased high density lipoprotein (HDL) cholesterol by 15%. The alterations, which were stable 4 weeks after the start of treatment, were not associated with any significant change in sperm quality, the seminal plasma concentrations of various sex gland products (prostate-specific acid phosphatase, polyamines, citrate, fructose, alpha-glucosidase), or the serum concentrations of cortisol, testosterone, LH, FSH, or prolactin. It is concluded that a short-term reduction in circulating LDL-cholesterol has no marked effect on testicular function or sperm quality.
...
PMID:Short-term effects of treatment with simvastatin on testicular function in patients with heterozygous familial hypercholesterolaemia. 154 17

We have previously presented evidence for the involvement of islet acid amyloglucosidase, a lysosomal glycogen-hydrolyzing enzyme, in certain insulin secretory processes. In the present investigation, we studied whether differential changes in islet amyloglucosidase activity could be related to the insulin secretory response to glucose. It was observed that the dose-response curve for glucose-induced insulin response in vivo was shifted to the left by pretreatment of mice with purified fungal amyloglucosidase. In enzyme-pretreated mice, the ED50 was 2.1 mmol/kg glucose as compared with 5.7 mmol/kg in saline-pretreated controls (p less than 0.005). Also, the maximal insulin response to glucose was enhanced by amyloglucosidase pretreatment. Parenteral administration to mice (four injections during 2 days) of the pseudotetrasaccharide acarbose, a recognized inhibitor of intestinal alpha-glucosidases, surprisingly induced a marked increase in the activities of islet acid amyloglucosidase (+ 120%; p less than 0.001) and acid alpha-glucosidase (+ 45%; p less than 0.01) without affecting the activities of other lysosomal enzymes such as acid phosphatase and N-acetyl-beta-D-glucosaminidase. No effect on the microsomal neutral alpha-glucosidase was recorded. Moreover, in these mice, the insulin secretory response to glucose was enhanced both at a maximal dose of glucose 11.1 mmol/kg and at a dose in the ED25-ED50 range, 3.3 mmol/kg (p less than 0.005). Direct addition of acarbose to islet homogenates strongly suppressed acid amyloglucosidase activity, the EC50 being approximately 1 microM. Acid alpha-glucosidase activity was also strongly inhibited, whereas the activities of acid phosphatase and N-acetyl-beta-D-glucosaminidase were unaffected. Neutral alpha-glucosidase was slightly suppressed.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:The relationship of islet amyloglucosidase activity and glucose-induced insulin secretion. 159 57

The trypanocidal drug suramin is known to concentrate in lysosomes and to depress the activity of different lysosomal enzymes. We have previously shown that suramin can inhibit the activity of the islet lysosomal enzyme acid amyloglucosidase, a glycogenolytic glucose-producing hydrolase, which seems to be involved in certain insulin-secretory processes. In the present investigation we studied the pH dependency and dose-response effects of suramin on islet lysosomal enzyme activities as well as the effect of suramin treatment on the insulin-secretory response to various secretagogues in mice. It was found that two injections of suramin (0.18 mmol/kg) to normal NMRI mice at -24 and -2 h induced a moderate depression of the activities of islet acid amyloglucosidase (-22%) and acid phosphatase (-13%), whereas no effect was recorded for the activities of acid alpha-glucosidase, N-acetyl-beta-D-glucosaminidase and the non-lysosomal enzyme neutral alpha-glucosidase. Direct addition of different concentrations of suramin to islet homogenates showed that the drug was a potent inhibitor of acid amyloglucosidase and acid alpha-glucosidase at pH 4.0. At pH 5.0, suramin induced a large increase in acid alpha-glucosidase activity, whereas acid amyloglucosidase and acid phosphatase were inhibited. Suramin-injected mice showed a reduced insulin-secretory response to the sulphonylurea drug glibenclamide (-45%), whereas the insulin response to the cholinergic agonist carbachol or the phosphodiesterase inhibitor IBMX (1-isobutyl-3-methylxanthine) was unaffected. It is concluded that suramin inhibits islet acid amyloglucosidase activity in vivo and in vitro, whereas its effect on acid alpha-glucosidase is complex and pH dependent.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Effect of the lysosomotropic drug suramin on islet lysosomal enzyme activities and the insulin-secretory response induced by various secretagogues. 172 7


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

---