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

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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 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

In this study we investigated the function of the obstructed small bowel of the rat, the behaviour of the mucosal enzymes, the metabolic changes of the small bowel wall and the morphology of the mucosa. We found a decrease of passive transport of 3H-Antipyrine which was equal after 24 and 48 hrs. The active transport of 14C-Glucose was found to be progressively inhibited after occlusion. The metabolic enzymes SDH, G-6-PDH, and GOT remained unchanged, LDH was increased after 48 hrs, which can be explained by enzyme induction. The lactate-pyruvate ratio in the tissue of the obstructed bowel was 3 times as high as in the controls. The brush-border enzymes maltase and especially the alkaline phosphatase are decreased with progressive obstruction, which probably is caused by diffusion into the lumen. By electron-microscopy there are no changes in the brush-border membrane but a swelling of mitochondria which is caused by hypoxia.
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PMID:[Functional and metabolic changes of the mucosa during the occlusion of the small bowel of the rat (author's transl)]. 121 48

Acemannan (ACE-M), a beta-(1,4)-linked acetylated mannan, was evaluated for in vitro activity against human immunodeficiency virus type 1 (HIV-1). Castanospermine (CAS), deoxymannojirimycin (DMN), swainsonine (SWS), azidothymidine (AZT), and dideoxythymidine (DDC) were tested in parallel as control compounds. In vitro antiviral efficacy of ACE-M was evaluated in a variety of cell lines including human peripheral mononuclear, CEM-SS1 and MT-2(2) cells. The virus strain, number of infectious units per cell, and target cell line were important factors in determining the degree of inhibition of viral cytopathic effect in the presence of ACE-M and other control compounds tested. Maximum inhibitory effect was observed in CEM-SS cells infected with the RFII strain of HIV-1. This inhibitory effect was determined to be concentration-dependent. Assay design included primary screening to measure cell viabilities of infected target cells in the presence and absence of test compounds. When tested on HIV-1/RFII-infected CEM-SS cells, the 50% inhibitory effect of CAS (IC50 = 28), an inhibitor of alpha-glucosidase I, was determined to be similar to that observed for ACE-M (IC50 = 45). However, DMN and SWS, inhibitors of mannosidase I and II, tested in parallel to CAS and ACE-M, exhibited no IC50 values. Antiviral potential of ACE-M as an inhibitor of syncytia formation was also explored using CEM-SS cells. Suppression of syncytia formation was observed at an ACE-M concentration of 31.25 micrograms/ml, and complete inhibition was observed at 62.5 micrograms/ml. In addition, HIV-1 RNA levels were studied to establish the antiviral potential of ACE-M in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inhibition of AIDS virus replication by acemannan in vitro. 176 65

The circadian rhythms of maltase, alkaline phosphatase and dipeptide hydrolase were assessed in duodenum, proximal, medial and distal parts of the rat small intestine. Functional activities were assessed every 4 hrs for 24 hrs. Patterns of all enzymatic activities were different in different parts. The mucosal protein content in each segment of intestine was constant throughout the 24-hour period.
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PMID:[Circadian rhythmicity of the enzyme activity of different portions of the small intestine]. 353 11

Glucose homeostasis is maintained by a balance between the release and action of insulin, and the counterregulatory responses mediated principally by glucagon, catecholamines, growth hormone and cortisol. Hence, the effects of a drug on glucose metabolism may be mediated by any of these agents singly or in combination. Host factors, such as inherent glucoregulatory mechanisms, concurrent diseases, organ function and concomitant medications also increase the risk of drug-induced disturbances of glucose homeostasis in susceptible individuals. By far the most important agents causing hypoglycaemia are insulin and the sulphonylureas. Alcohol (ethanol), over-zealous glycaemic control, hypoglycaemic unawareness, detective counterregulation especially in insulin-dependent diabetes mellitus (IDDM), and renal and liver impairment are all important predisposing factors. Although antihyperglycaemic agents such as metformin and alpha-glucosidase inhibitors do not cause hypoglycaemia alone, they may enhance the hypoglycaemic effects of potent hypoglycaemic agents such as insulin and sulphonylureas. On the other hand, the potential hypoglycaemic effects of ACE inhibitors, alpha-blockers, lipid-lowering agents and recombinant human insulin-like growth factor demonstrated in experimental settings, are of potential therapeutic interest. Iatrogenic hypoglycaemia and intensive insulin treatment are associated with hypoglycaemic unawareness which may be obviated by meticulous avoidance of hypoglycaemia. Effective patient education remains an important preventive measure. Oral glucose is used to treat mild hypoglycaemic episodes while more severe episodes are treated by intravenous glucose or glucagon. Nasal glucagon and theophylline are other experimental measures to improve recovery from hypoglycaemia. In refractory hypoglycaemia due to hyperinsulinaemia such as during sulphonylurea overdosage or quinine treatment, the long-acting somatostatin, octreotide, may suppress insulin release and restore euglycaemia. Diuretics, beta-blockers, sympathomimetics, corticosteroids and sex hormones are commonly prescribed drugs which may have adverse effects on carbohydrate metabolism especially in patients with diabetes mellitus or those who are at risk of developing glucose intolerance. Pentamidine was frequently associated with dysglycaemia due to its pancreatic beta-cell cytotoxic effects but is now used less often to treat Pneumocystis carinii pneumonia in immunosuppressed patients. Despite the large number of anecdotal reports of drug-induced disturbances of glucose metabolism, many of the so-called adverse drug reactions were either idiosyncratic or coincidental. Nevertheless, they emphasise the complex nature of glucose homeostasis and its potential interactions with drugs, host factors and disease states. An understanding of these relationships may allow more critical interpretation of these clinical observations, better prediction of drug induced adverse effects on carbohydrate metabolism and the implementation of more rational therapy. Hence, the hypoglycaemic effects of a drug may be turned to a therapeutic advantage in patients with glucose intolerance. Similarly, the hyperglycaemic effect of a drug may help to treat refractory hypoglycaemia.
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PMID:Drug-induced disorders of glucose metabolism. Mechanisms and management. 888 64

The sites of glycosylation of Chinese hamster ovary cell expressed testicular angiotensin-converting enzyme (tACE) have been determined by matrix-assisted laser desorption ionization/time of flight/mass spectrometry of peptides generated by proteolytic and cyanogen bromide digestion. Two of the seven potential N-linked glycosylation sites, Asn90 and Asn109, were found to be fully glycosylated by analysis of peptides before and after treatment with a series of glycosidases and with endoproteinase Asp-N. The mass spectra of the glycopeptides exhibit characteristic clusters of peaks which indicate the N-linked glycans in tACE to be mostly of the biantennary, fucosylated complex type. This structural information was used to demonstrate that three other sites, Asn155, Asn337, and Asn586, are partially glycosylated, whereas Asn72 appears to be fully glycosylated. The only potential site that was not modified is Asn620. Sequence analysis of tryptic peptides obtained from somatic ACE (human kidney) identified six glycosylated and one unglycosylated Asn. Only one of these glycosylation sites had a counterpart in tACE. Comparison of the two proteins reveals a pattern in which amino-terminal N-linked sites are preferred. The functional significance of glycosylation was examined with a tACE mutant lacking the O-glycan-rich first amino-terminal 36 residues and truncated at Ser625. When expressed in the presence of the alpha-glucosidase I inhibitor N-butyldeoxynojirimycin and treated with endoglycosidase H to remove all but the terminal N-acetylglucosamine residues, it retained full enzymatic activity, was electrophoretically homogeneous, and is a good candidate for crystallographic studies.
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PMID:Identification of N-linked glycosylation sites in human testis angiotensin-converting enzyme and expression of an active deglycosylated form. 901 98

Insulin resistance plays an important role in the pathogenesis of metabolic syndrome and hence an improvement of insulin resistance is important in the treatment of metabolic syndrome. Oral hypoglycemic agents such as thiazolidinediones and biguanides improve glycemic control by reducing insulin resistance. Furthermore, it has been clarified that they also have anti-dyslipidemic, anti-hypertensive and anti-atherosclerotic actions. In addition, such an insulin sensitizing effect has been demonstrated when alpha-glucosidase inhibitors, statins, fibrates and hypotensive agents such as ACE inhibitors, calcium channel blockers and ARBs have been given to patients with insulin resistance. These drugs should be used for each patient on the basis of the underlying diseases, in addition to a lifestyle modification.
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PMID:[Total care for patients with metabolic syndrome]. 1520 58

Long-term type 2 diabetes can lead to numerous biological complications, such as hypertension and cardio-vascular disease. Key enzymes involved in the enzymatic breakdown of complex carbohydrates,pancreatic alpha-amylase and intestinal alpha-glucosidase, have been targeted as potential avenues for modulation of type 2 diabetes-associated post-prandial hyperglycemia through mild inhibition of their enzymatic activities so as to decrease meal-derived glucose absorption. Further, inhibition of hypertension-linked angiotensin I-converting enzyme (ACE) was targeted as a potential approach for modulation of diabetes-linked hypertension. Water-soluble extracts of soybean optimized for phenolic content via sprouting or bioprocessing by dietary fungus (Rhizopus oligosporus, Lentinus edodes) were investigated for inhibitory activity against porcine pancreatic alpha-amylase (PPA), yeast alpha-glucosidase, and rabbit lung ACE in vitro. PPA was allowed to react with each phenolic-optimized extract and the derivatized enzyme-phytochemical mixtures obtained were characterized for residual amylase activity. Alpha-glucosidase and ACE activities were determined in the presence of each phenolic-optimized extract. All of the soybean extracts possessed marked anti-amylase activity, with extracts of R. oligosporus-bioprocessed soybean having the strongest inhibitory activity, but only slight anti-glucosidase activity. The anti-amylase activity of each extract seemed associated with extract antioxidant activity. Anti-enzyme activity was slightly associated with total soluble phenolic content per se, but seemed more associated to the length of sprouting or bioprocessing of the soybean substrate. Short-term sprouting or bioprocessing seemed to improve anti-amylase activity, while long-term sprouting or bioprocessing seemed to aid anti-glucosidase activity. While ACE activity was strongly inhibited by all of the soybean extracts (44-97%), only sprouting was found to increase this inhibition and bioprocessing of soybean with L. edodes decreased inhibitory activity of soybean extract. The results suggest that sprouting and dietary fungal bioprocessing of soybean improve the anti-diabetic potential of soybean extracts, potentially through modulation of the phenolic profile of the extract, and further suggest that enzyme inhibitory activity may be linked to phenolic antioxidant mobilization during spouting and/ or bioprocessing. The significance of food-grade, plant-based enzyme inhibitors for modulation of carbohydrate breakdown and control of glycemic index of foods in the context of preventing hyperglycemia and diabetes mellitus complications such as hypertension in the long-term is hypothesized and discussed.
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PMID:Anti-diabetic and anti-hypertensive potential of sprouted and solid-state bioprocessed soybean. 1592 31

Because management of type 2 diabetes mellitus usually involves combined pharmacological therapy to obtain adequate glucose control and treatment of concurrent pathologies (especially dyslipidaemia and arterial hypertension), drug-drug interactions must be carefully considered with antihyperglycaemic drugs. Additive glucose-lowering effects have been extensively reported when combining sulphonylureas (or the new insulin secretagogues, meglitinide derivatives, i.e. nateglinide and repaglinide) with metformin, sulphonylureas (or meglitinide derivatives) with thiazolidinediones (also called glitazones) and the biguanide compound metformin with thiazolidinediones. Interest in combining alpha-glucosidase inhibitors with either sulphonylureas (or meglitinide derivatives), metformin or thiazolidinediones has also been demonstrated. These combinations result in lower glycosylated haemoglobin (HbA(1c)), fasting glucose and postprandial glucose levels than with either monotherapy. Even if modest pharmacokinetic interferences have been reported with some combinations, they do not appear to have important clinical consequences. No significant adverse effects, except a higher risk of hypoglycaemic episodes that may be attributed to better glycaemic control, occur with any combination. Challenging the classical dual therapy with sulphonylurea plus metformin, there is a recent trend to use alternative dual combinations (sulphonylurea plus thiazolidinedione or metformin plus thiazolidinedione). In addition, triple therapy with the addition of a thiazolidinedione to the metformin-sulphonylurea combination has been recently evaluated and allows glucose targets to be reached before insulin therapy is considered. This triple therapy appears to be safe, with no deleterious drug-drug interactions being reported so far.Potential interferences may also occur between glucose-lowering agents and other drugs, and such drug-drug interactions may have important clinical implications. Relevant pharmacological agents are those that are widely coadministered in diabetic patients (e.g. lipid-lowering agents, antihypertensive agents); those that have a narrow efficacy/toxicity ratio (e.g. digoxin, warfarin); or those that are known to induce (rifampicin [rifampin]) or inhibit (fluconazole) the cytochrome P450 (CYP) system. Metformin is currently a key compound in the pharmacological management of type 2 diabetes, used either alone or in combination with other antihyperglycaemics. There are no clinically relevant metabolic interactions with metformin, because this compound is not metabolised and does not inhibit the metabolism of other drugs. In contrast, sulphonylureas, meglitinide derivatives and thiazolidinediones are extensively metabolised in the liver via the CYP system and thus, may be subject to drug-drug metabolic interactions. Many HMG-CoA reductase inhibitors (statins) are also metabolised via the CYP system. Even if modest pharmacokinetic interactions may occur, it is not clear whether drug-drug interactions between oral antihyperglycaemic agents and statins may have clinical consequences regarding both efficacy and safety. In contrast, a marked pharmacokinetic interference has been reported between gemfibrozil and repaglinide and, to a lesser extent, between gemfibrozil and rosiglitazone. This leads to a drastic increase in plasma concentrations of each antihyperglycaemic agent when they are coadministered with the fibric acid derivative, and an increased risk of adverse effects. Some antihypertensive agents may favour hypoglycaemic episodes when co-prescribed with sulphonylureas or meglitinide derivatives, especially ACE inhibitors, but this effect seems to result from a pharmacodynamic drug-drug interaction rather than from a pharmacokinetic drug-drug interaction. No, or only modest, interferences have been described with glucose-lowering agents and other pharmacological compounds such as digoxin or warfarin. The effects of inducers or inhibitors of CYP isoenzymes on the metabolism and pharmacokinetics of the glucose-lowering agents of each pharmacological class has been tested. Significantly increased (with CYP inhibitors) or decreased (with CYP inducers) plasma levels of sulphonylureas, meglitinide derivatives and thiazolidinediones have been reported in healthy volunteers, and these pharmacokinetic changes may lead to enhanced or reduced glucose-lowering action, and thus hypoglycaemia or worsening of metabolic control, respectively. In addition, some case reports have evidenced potential drug-drug interactions with various antihyperglycaemic agents that are usually associated with a higher risk of hypoglycaemia.
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PMID:Drug interactions of clinical importance with antihyperglycaemic agents: an update. 1596 7

In the current study, we screened 7 clonal lines from single seed phenotypes of Lamiaceae family for the inhibition of alpha-amylase, alpha-glucosidase and angiotensin converting enzyme (ACE) inhibitory activity. Water extracts of oregano had the highest alpha-glucosidase inhibition activity (93.7%), followed by chocolate mint (85.9%) and lemon balm (83.9%). Sage (78.4 %), and three different clonal lines of rosemary: rosemary LA (71.4%), rosemary 6 (68.4%) and rosemary K-2 (67.8%) also showed significant alpha-glucosidase inhibitory activity. The alpha-glucosidase inhibitory activity of the extracts was compared to selected specific phenolics detected in the extracts using HPLC. Catechin had the highest alpha-glucosidase inhibitiory activity (99.6 %) followed by caffeic acid (91.3 %), rosmarinic acid (85.1%) and resveratrol (71.1 %). Catechol (64.4%), protocatechuic acid (55.7%) and quercetin (36.9%) also exhibited significant alpha-glucosidase inhibitory activity. Results suggested that alpha-glucosidase inhibitory activity of the clonal extracts correlated to the phenolic content, antioxidant activity and phenolic profile of the extracts. The clonal extracts of the herbs and standard phenolics tested in this study did not have any effect on the alpha-amylase activity. We also investigated the ability of the clonal extracts to inhibit rabbit lung angiotensin I-converting enzyme (ACE). The water extracts of rosemary, rosemary LA had the highest ACE inhibitory activity (90.5%), followed by lemon balm (81.9%) and oregano (37.4 %). Lower levels of ACE inhibition were observed with ethanol extracts of oregano (18.5 %) and lemon balm (0.5 %). Among the standard phenolics only resveratrol (24.1 %), hydroxybenzoic acid (19.3 %) and coumaric acid (2.3 %) had ACE inhibitory activity.
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PMID:Evaluation of clonal herbs of Lamiaceae species for management of diabetes and hypertension. 1650 Aug 86


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