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)

Castanospermine (CSP) inhibits alpha-glucosidase, which is involved in the initial step of N-linked oligosaccharide processing of secretory and membrane glycoproteins. In Staphylococcus aureus Cowan I (SAC)-stimulated human lymphocyte culture, CSP at a dose of 20 micrograms/ml caused a twofold increase in immunoglobulin G (IgG) release after 7 days. An initial 48-h exposure to CSP sufficed for this enhancing effect. Plaque-forming cell assays on the seventh day disclosed that CSP caused an increase in the number of IgG-, IgA- and IgM-secreting cells. In cross-culture experiments, only a mixture of B cells pretreated with CSP and untreated T cells showed an increase in IgG production. Tritiated thymidine incorporation studies revealed that CSP enhanced B-cell responses to T cell-derived soluble factor (TSF). When incubated with CSP for 18 h, B cells showed an increased surface binding on [3H]concanavalin A (Con A). These results indicate that the alteration in B-cell membrane oligosaccharides enhances the response to TSF at an early stage of SAC culture, leading to an increase in Ig-secreting cell number at later stages. The present study provides evidence that cell-surface oligosaccharides of B cells play an important role in the responses of B cells to lymphokines.
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PMID:Alteration of membrane oligosaccharides by castanospermine, an alpha glucosidase inhibitor, enhances immunoglobulin production in Staphylococcus aureus Cowan I-stimulated lymphocyte culture. 227 Apr 34

Seven known alpha-glucosidase/beta-fructosidase inhibitors were examined for inhibitory effect against invertases in pooled human dental plaque. The inhibitors used were acarbose, Trestatin, nojirimycin, 1-deoxynojirimycin, glucono-delta-lactam, conduritol-B-epoxide, and Hoe 467A. Plaque homogenates were incubated with 14C-labelled sucrose and invertase activity was assayed by determination of radio-labelled monosaccharide after paper chromatography. Conduritol-B-epoxide, acarbose, and Trestatin reduced the invertase activity an average of 62%, 51%, and 35% respectively. The other inhibitors affected the enzyme activity negligibly. By combining conduritol-B-epoxide with acarbose or Trestatin in other plaque homogenates the inhibition of invertases increased from 35% to 61%. This observation supported the concept that the invertases in dental plaque consist of both alpha-glucosidases and beta-fructosidases.
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PMID:Effect of seven inhibitors on invertases in homogenates of human dental plaque. 622 87

Samples of 2-day plaque were collected before and during two 25-day diet periods from 24 subjects taking part in a double-blind cross-over study involving sucrose- and maltose-rich diets. The mean change in plaque pH measured after exposure to the respective sugar during the 3rd week of both diet periods was similar. The dry weight of plaque did not vary significantly as either diet progressed but the lowest mean value obtained was in the 4th week of the maltose diet. The extracellular polysaccharide content of plaque was lower in the maltose group than in the sucrose group (p = 0.052). Plaque-invertase activity was not affected significantly by the diets but maltase activity was significantly higher in the 2nd and 4th weeks of the maltose diet (p = 0.039; p = 0.012). The results suggest that the polysaccharide matrix of plaque formed in the presence of maltose as opposed to sucrose is different, which could be explained by the known effect of maltose in vitro on plaque glucosyl transferases.
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PMID:The influence of the replacement of dietary sucrose by maltose on the formation and biochemistry of human dental plaque. 695 74