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)

On the basis of literary data is made a profound survey of the place of the final stages of the sugars and peptides hydrolysis in the small intestine. It is pointed out that whereas it has been proved for the oligosaccharides to be situated on the surface of the enterocyte membranes the discussion on the cytoplasmic and membrane localization of the most dipeptidases has not ended up yet. In our own experimental investigation it has been established that the repeated washing of the small intestine with Ringer solution reduces the maltase activity whereas the glycyl-glycin dipeptidase activity does not change. This confirms the surface membrane localization of the disaccharidase while the dipeptidase is evidently not there. Due to the low pH in the cytoplasm the glycyl-glycin-dipeptidase is considered hardly likely to be localized intracellularly. A hypothesis is advanced according to which this enzyme is structurally related to the enterocyte membranes, his catalytic centre being in the membranes themselves. In this way hydrolysis is realized in the membrane pores as well, which allows the supposition that there exists intramembrane digestion.
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PMID:On the possibilities of existence of enzymatic hydrolysis in the membranes themselves of the intestinal epithelial cells. 885 51

The adaptive modulation hypothesis posits that the expression of digestive proteins should be modulated in response to intake of their respective substrates. A corollary of this hypothesis suggests that dietary flexibility and digestive plasticity should be correlated. We examined these two hypotheses in two granivorous Chilean birds (Zonotrichia capensis and Diuca diuca) that differ in dietary breadth. D. diuca is a strict granivore, whereas Z. capensis also eats insects. In field-caught birds, the activity of the intestinal dipeptidase aminopeptidase-N was positively correlated with intake of insects in Z. capensis but not in D. diuca. This is the first field documentation of modulation of intestinal enzymes by diet in birds. Intestinal maltase and sucrase activities were not correlated with seed (vs. insect) intake in either species. In the laboratory, captive birds of both species exhibited similar modulation of membrane-bound intestinal hydrolases when fed on synthetic diets of contrasting carbohydrate and protein composition. Maltase, sucrase, and aminopeptidase-N activities were significantly higher in birds fed on the carbohydrate-free than those on the carbohydrate-containing diet. Activities of the three enzymes were positively correlated. Therefore, this increase probably resulted from nonspecific increases of all enzymes resulting from intake of the carbohydrate-free diet. Principal components analysis separating the effect of diet on specific and on nonspecific modulation revealed that diet had a strong effect on nonspecific activity of intestinal enzymes in both Z. capensis and D. diuca. Diet also significantly affected aminopeptidase-N activities when the effect of diet on nonspecific modulation was removed. Birds fed on the carbohydrate-free, high-protein diet had significantly higher specific aminopeptidase-N activities than those fed on the carbohydrate-containing diet. Our results cast doubts on the notion that dietary flexibility and the plasticity of the gut's enzymes are necessarily correlated and on the general validity of the adaptive modulation hypothesis.
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PMID:Dietary flexibility and intestinal plasticity in birds: a field and laboratory study. 954 55

Although several previous studies have been published on the effects of dipeptidase-4 (DPP-4) inhibitors in diabetic hemodialysis (HD) patients, the findings have yet to be reviewed comprehensively. Eyesight failure caused by diabetic retinopathy and aging-related dementia make multiple daily insulin injections difficult for HD patients. Therefore, we reviewed the effects of DPP-4 inhibitors with a focus on oral antidiabetic drugs as a new treatment strategy in HD patients with diabetes. The following 7 DPP-4 inhibitors are available worldwide: sitagliptin, vildagliptin, alogliptin, linagliptin, teneligliptin, anagliptin, and saxagliptin. All of these are administered once daily with dose adjustments in HD patients. Four types of oral antidiabetic drugs can be administered for combination oral therapy with DPP-4 inhibitors, including sulfonylureas, meglitinide, thiazolidinediones, and alpha-glucosidase inhibitor. Nine studies examined the antidiabetic effects in HD patients. Treatments decreased hemoglobin A1c and glycated albumin levels by 0.3% to 1.3% and 1.7% to 4.9%, respectively. The efficacy of DPP-4 inhibitor treatment is high among HD patients, and no patients exhibited significant severe adverse effects such as hypoglycemia and liver dysfunction. DPP-4 inhibitors are key drugs in new treatment strategies for HD patients with diabetes and with limited choices for diabetes treatment.
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PMID:Diabetes therapies in hemodialysis patients: Dipeptidase-4 inhibitors. 2613 25


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