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 initial management of non-insulin-dependent diabetes mellitus (NIDDM) should include patient education, dietary counselling and, when feasible, individualised physical activity. It is only when such measures fail that drug therapy should be considered. Dietary management of NIDDM includes a restriction in calories, and these should be appropriately distributed as carbohydrates, lipids and proteins. Supplementation of the diet with soluble fibre and supplementation with magnesium salts if hypomagnesaemia is demonstrated, is recommended. However, supplementation with fish oils or with fish oil-derived omega-3 fatty acids is not currently recommended. Oral drug therapies used in NIDDM include sulphonylurea derivatives, which are a first-line treatment in patients who are not grossly obese, metformin, which is the treatment of choice for obese patients, and alpha-glucosidase inhibitors such as acarbose, which are used mainly to reduce postprandial blood glucose peaks. These types of drugs can be used alone or in combination. Insulin therapy may be required to achieve adequate control of blood glucose levels in some patients. In several instances, it is suggested that insulin therapy be combined with sulphonylureas (essentially when residual insulin secretion is present), with metformin, or with alpha-glucosidase inhibitors. The treatment of disorders associated with NIDDM, such as obesity, hypertension or hyperlipidaemia, requires particular attention in diabetic patients, since some drugs can adversely affect glycaemic control. Oral drugs for the treatment of NIDDM include sulphonylurea derivatives used in first-line treatment in patients who are not grossly obese, metformin, which is often the treatment of choice for obese patients and, more recently, the alpha-glucosidase inhibitors, such as acarbose, which are effective in reducing the postprandial rise in blood glucose.
 ...
PMID:Management of non-insulin-dependent diabetes mellitus. 128 May 75

Acarbose, an alpha-glucosidase inhibitor, delays absorption of carbohydrate in the gut, thereby lowering postprandial glucose levels. Safety data on this drug have been gathered in a series of studies on animals and in extensive clinical trials in humans. Although an initial long term feeding study in rats showed an excess of renal tumours at very high dosages of acarbose (up to 300 mg/kg bodyweight daily), further evaluation with similar studies in rats, hamsters, and dogs indicated that the problem was related to carbohydrate malabsorption. With adequate glucose intake and in gavage studies, no difference in tumour incidence between placebo- and acarbose-treated groups was seen. From 1976 to 1989, safety data on acarbose were obtained in approximately 8800 patients in 2 separate groups of clinical trials, the Bayer International Clinical Data Pool and the American phase III trials. Almost all adverse experiences, as reported by 56 to 76% of patients on acarbose vs 32 to 37% of patients on placebo, were related to the digestive system and included diarrhoea, flatulence, bloating and nausea. Most symptoms were of mild to moderate intensity and tended to improve with time. In the American trials a small but significant increase in liver transaminases was seen, 3.8% in acarbose-treated patients vs 0.9% in controls together with a 1% increase in anaemia in the acarbose group. Overall, acarbose was well tolerated and the adverse experience profile was clinically acceptable.
 ...
PMID:Safety profile of acarbose, an alpha-glucosidase inhibitor. 128 May 77

We investigated enzymes participating in alpha-glucoside formation, a novel metabolic pathway of xenobiotics in a metabolic study of indeloxazine hydrochloride in rats. When rat tissue homogenates and the indeloxazine metabolite trans-4-(2-morpholinylmethoxy)-1,2-indandiol (M-2) were incubated, M-2-alpha-glucoside formation was observed in liver. This reaction was almost completely inhibited by the alpha-glucosidase inhibitor acarbose. The liver homogenate was then separated into subcellular fractions and an acid alpha-glucosidase in lysosomes and two neutral alpha-glucosidases in microsomes and cytosol were partially purified. The chromatographic behavior and optimum pH of the glucosyltransferase activity of each of the enzyme preparations were almost identical with those of alpha-glucosidase (hydrolase) activity of the same specimen, suggesting the former activity to be also due to alpha-glucosidase. Agreeing with their hydrolytic substrate specificities, the acid enzyme transferred glucose to M-2 from a series of glucose derivatives, ranging from low molecular maltosaccharides to high molecular glycogen, whereas the neutral enzymes took only low molecular maltosaccharides as glucosyl donors. These results led to the conclusion that the formation of alpha-glucoside conjugates is catalyzed by more than one alpha-glucosidase in the liver and uses maltosaccharides or glycogen as glucosyl donors. Several other diol structure-bearing compounds were found in vitro to give rise to alpha-glucoside conjugates, and the mechanism of alpha-glucoside formation is discussed.
 ...
PMID:Alpha-glucoside formation of xenobiotics by rat liver alpha-glucosidases. 135 26

The chronic diarrhea observed in young malnourished infants that is sensitive to dietary glucose and other carbohydrates is associated with variable degrees of patchy mucosal villous atrophy. To explore intrinsic mucosal function in the pathogenesis of this alimentary intolerance, we have conducted an immunohistologic investigation of brush-border enzyme proteins of clinically obtained, mucosal biopsy samples. We used a group of monoclonal antibodies against human brush-border aminopeptidase, sucrase/isomaltase (SI), maltase, and lactase enzyme proteins. SI was strongly and uniformly expressed in crypts and villi of 11 of the 14 subjects; in 3 subjects, however, SI was expressed in a mosaic pattern. Maltase and lactase were occasionally absent, but more commonly were expressed in a mosaic distribution. The mosaic expression of brush-border enzyme proteins has been reported in congenital enzyme deficiencies associated with normal intestinal histology. We report the mosaic expression of brush-border enzyme proteins as a functional alteration associated with a pathological lesion of the mucosa in infants with chronic diarrhea. Our observation challenges the existing concept of ontogenic regulation of brush-border enzyme activity.
 ...
PMID:Mosaic expression of brush-border enzymes in infants with chronic diarrhea and malnutrition. 135 33

In order to isolate the structural gene involved in sucrose utilization, we screened a sucrose-induced Candida albicans cDNA library for clones expressing alpha-glucosidase activity. The C. albicans maltase structural gene (CAMAL2) was isolated. No other clones expressing alpha-glucosidase activity. were detected. A genomic CAMAL2 clone was obtained by screening a size-selected genomic library with the cDNA clone. DNA sequence analysis reveals that CAMAL2 encodes a 570-amino-acid protein which shares 50% identity with the maltase structural gene (MAL62) of Saccharomyces carlsbergensis. The substrate specificity of the recombinant protein purified from Escherichia coli identifies the enzyme as a maltase. Northern (RNA) analysis reveals that transcription of CAMAL2 is induced by maltose and sucrose and repressed by glucose. These results suggest that assimilation of sucrose in C. albicans relies on an inducible maltase enzyme. The family of genes controlling sucrose utilization in C. albicans shares similarities with the MAL gene family of Saccharomyces cerevisiae and provides a model system for studying gene regulation in this pathogenic yeast.
 ...
PMID:Cloning and characterization of a Candida albicans maltase gene involved in sucrose utilization. 140 Feb 49

The small intestinal disaccharidase activity and its daily variation in the diabetic rat have not been well described. Therefore, the small intestinal disaccharidase (maltase, lactase and sucrase) activity and its daily profile were studied in streptozotocin-induced diabetic rats under physiological conditions. In diabetic rats, a similar pattern of diurnal variation of disaccharidase activity to control rats was observed, while the relationships between daily change of disaccharidase activity and that of food consumption suggested that there was a different mechanism of diurnal variation in diabetic rats. On the other hand, a significant increase of mean 24-h lactase and sucrase activities was noted in diabetic rats, while that of maltase was not significant. Using the in vitro incubation method, a significant correlation between glucose concentration and lactase or sucrase activity but not maltase activity was observed. However, insulin showed no effect on disaccharidase activity. Thus we clarified the presence of a diurnal variation of disaccharidase activity and an increase in its activity in diabetic rats. This change was suggested to be derived from high plasma glucose level.
 ...
PMID:Diurnal variation and increase of disaccharidase activity in diabetic rats. 145 37

The high molecular weight glycogen associated with the lysosomal compartment in glycogen storage disease type VIII is more resistant to degradation by proteinase than normal glycogen. The assembly of large glycogen particles on disulphide-linked protein backbones has been confirmed and the disulphide-reducing nature of the lysosome appears to confer an advantage in the amylolytic degradation of glycogen. Experiments utilising acarbose, a lysosomal (1----4)-alpha-D-glucosidase inhibitor, show that some blood glucose could arise in normal mammals from extra-hepatic tissue, by degradation of the glycogen in the lysosomal compartment.
 ...
PMID:Molecular and metabolic aspects of lysosomal glycogen. 149 32

The effect of the alpha-glucosidase inhibitor acarbose on postprandial hyperglycaemia was explored in the spontaneously diabetic BB/W-rat. Acarbose-treatment (5 mg.kg body weight-1.day-1) of diabetic BB/W-rats maintained on small doses of insulin, was associated with a 40% reduction in the 24-h glucose area compared to non-treated diabetic rats. Over a 4 month treatment period this reduction in cumulative hyperglycaemia resulted in a complete prevention of autonomic polyneuropathy as indicated by R-BAR values. The development of somatic polyneuropathy in the BB/W-rat was significantly attenuated by acarbose treatment with a partial prevention of the characteristic nerve conduction velocity slowing during the first 3 months of diabetes, but no longer at 4 months. Characteristic structural abnormalities associated with diabetes in this model, such as axonal atrophy and axo-glial dysjunction, were significantly but only partially prevented in rats treated with acarbose for a diabetes duration of 4 months. These data suggest that postprandial lowering of hyperglycaemia resulting in a decrease in cumulative hyperglycaemia retards the development of diabetic polyneuropathies in the BB/W-rat.
 ...
PMID:Long-term suppression of postprandial hyperglycaemia with acarbose retards the development of neuropathies in the BB/W-rat. 151 60

Oral acarbose, a competitive inhibitor of alpha-glucosidase, has been shown to be effective in decreasing the postprandial rise in blood glucose and insulin. A double blind, cross-over, placebo controlled, randomized study in poorly controlled, non-insulin dependent diabetic patients under treatment with sulfonylureas was carried out. The patients continued receiving sulfonylureas throughout the study period and were randomly allocated into two sequences. In sequence A they received 100 mg tablets tid during 12 weeks; placebo tid during 2 weeks (wash-out period) and finally they were crossed over to placebo tid during 12 weeks. In sequence B, they received placebo tid 12 weeks, placebo tid during 2 weeks and finally acarbose 100 mg tid during 12 weeks. Sixteen patients were included in each sequence; three were excluded from sequence A, one because of side effects, one because of severe neuropathy and one because of change of address. One was excluded from sequence B because of failure to take the sulfonylurea. A slight but statistically significant decrease in weight was observed with acarbose as compared with placebo in both sequences. Significant reductions in postprandial glucose were observed in both sequences with acarbose. Significant reductions in fasting blood glucose were also observed in some visits. Although lower mean values of triglycerides and HbA1c were observed with acarbose, they were not statistically significant. Acarbose had side effects almost in all patients, but decreased on continued therapy. Only one patient had to be excluded for this cause. Acarbose is a useful therapeutic resource in poorly controlled non-insulin dependent diabetic patients in combination with sulfonylureas.
 ...
PMID:[Efficacy and tolerance to acarbose in non-insulin-dependent diabetics]. 152 53

Maltose fermentation in Saccharomyces yeasts requires one of five unlinked MAL loci: MAL1, 2, 3, 4, or 6. Each locus consists of three genes encoding maltose permease, maltase and the MAL activator. At MAL6 the genes are called MAL61, MAL62 and MAL63, respectively. Transcription of MAL61 and MAL62 is coordinately induced by maltose and repressed by glucose and this regulation is mediated by the MAL activator. By deletion analysis of the MAL61-MAL62 intergenic region, we show that a 68-basepair region, from base pairs -515 to -582 upstream of the MAL61 start codon, contains a sequence necessary for the maltose-induced expression of MAL61 and MAL62, the UAS(MAL). This sequence contains two copies of an 11-basepair dyad which may be the active elements of the UAS(MAL). Using heterologous gene plasmid constructs, we demonstrate that the UAS(MAL) sequence is sufficient for maltose inducibility of MAL62 and that this regulated expression requires a functional MAL activator. Our results suggest that the MAL61-MAL62 intergenic region contains additional distinct elements which function to precisely regulate MAL61 and/or MAL62 expression. Among these are repressing sequences, including a glucose-responsive element located between base pairs -583 and -638, which is partially responsible for mediating glucose-repression of MAL62 expression.
 ...
PMID:The UAS(MAL) is a bidirectional promotor element required for the expression of both the MAL61 and MAL62 genes of the Saccharomyces MAL6 locus. 152 71


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