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At least 919 records · Page 51Linked to original sources
PubMed1991

Effects of chlorhexidine on proteolytic and glycosidic enzyme activities of dental plaque bacteria.

Chlorhexidine was tested for its ability to inhibit a wide range of glycosidic and proteolytic enzyme activities produced by Treponema denticola, Porphyromonas gingivalis, Bacteroides intermedius, Actinobacillus actinomycemcomitans, Capnocytophaga sputigena, Capnocytophaga gingivalis, Capnocytophaga orchracea, Capnocytophaga sp., Actinomyces viscosus, Streptococcus mitior, Streptococcus mutans, Streptococcus sobrinus, Streptococcus mitis, Streptococcus anginosus, Streptococcus oralis and Streptococcus sanguis. The enzymes produced by Capnocytophaga spp. were the most resistant to inhibition by chlorhexidine while the hydrolysis of proteolytic substrates by all the other species was markedly susceptible to inhibition with less than 0.125 mM chlorhexidine inhibiting enzyme activities by greater than or equal to 50%. Glycosidase activities, of all species, were generally more resistant to inhibition, especially neuraminidase activity. Chlorhexidine at less than 0.032 mM inhibited the degradation of bovine serum albumin by suspensions of dental plaque bacteria. These observations support an hypothesis that chlorhexidine exerts a bacteristatic effect in vivo, in part, by reducing the ability of dental plaque bacteria to degrade host-derived proteins and glycoproteins which normally provide essential nutrients for growth.

Acetylglucosaminidase↗
PubMed1982

Effect of the alpha-glucosidase inhibitor, acarbose, on disaccharide splitting enzymes in human dental plaque.

Inhibition of microbial enzymes in human dental plaque catalyzing the cleavage of the disaccharides maltose, sucrose and lactose was carried out with the alpha-glucosidase inhibitor, acarbose. The maltases from plaque homogenates were totally inhibited, whereas the inhibition of the invertases varied considerably. With increasing inhibitor concentrations, from 1 mM to 50 mM, the inhibition of the invertases increased. Preincubation for 30 min of the plaque homogenate with inhibitor resulted in a 20% increase of the inhibition of invertase activity. The inhibitor showed non-competitive inhibition of the invertases in the homogenates, whereas the maltases were competitively inhibited. The lactases were not inhibited at all. The invertases from human dental plaque may be alpha-glucosidases and/or beta-fructosidases.

Acarbose↗
PubMed1983

Effect of seven inhibitors on invertases in homogenates of human dental plaque.

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.

1-Deoxynojirimycin↗
PubMed2003

Acarviosine-simmondsin, a novel compound obtained from acarviosine-glucose and simmondsin by Thermus maltogenic amylase and its in vivo effect on food intake and hyperglycemia.

Simmondsin was modified with acarviosine-glucose using the transglycosylation activity of Thermus maltogenic amylase to synthesize a novel compound with both antiobesity and hypoglycemic activity. The LC/MS and 13C NMR analyses confirmed that the structure of the major transglycosylation product was acarviosine-simmondsin (Acv-simmondsin), in which acarviosine was attached to the glucose moiety of simmondsin by an alpha-(1,6)-glycosidic linkage. It was found that Acv-simmondsin was a potent competitive inhibitor of alpha-glucosidase with the Ki value of 0.69 microM and a mixed type inhibitor of alpha-amylase with the Ki and KI of 20.78 microM and 26.31 microM, respectively. The administration of Acv-simmondsin (0.1 g/100 g diet/day) to mice for 5 days significantly reduced food intake by 35%, compared to 25% with simmondsin in control obese mice. Acv-simmondsin (50 mg/kg BW) suppressed the postprandial blood glucose response to sucrose (1 g/kg BW) by 74%, compared to 71% with acarbose, in normal rats.

Acetonitriles↗
PubMed2000

Alkaloidal sugar mimetics: biological activities and therapeutic applications.

Alkaloids mimicking the structures of sugars inhibit glycosidases because of a structural resemblance to the sugar moiety of the natural substrate. Glycosidases are involved in a wide range of important biological processes, such as intestinal digestion, post-translational processing of glycoproteins and the lysosomal catabolism of glycoconjugates. The realization that alkaloidal sugar mimics might have enormous therapeutic potential in many diseases such as viral infection, cancer and diabetes led to increasing interest and demand for these compounds. In this review, the structural basis of the specificity of alkaloidal sugar mimics and their current and potential applications to biomedical problems are reviewed.

Alkaloids↗
PubMed1989

Preparation of 3-amino-3-deoxy derivatives of trehalose and sucrose and their activities.

The 3-keto derivatives of trehalose and sucrose respectively were prepared by a one-step enzymatic route using D-glucoside 3-dehydrogenase from Flavobacterium saccharophilum. Reductive amination of 3-ketotrehalose with ammonium acetate and sodium cyanoborohydride gave three compounds, 3-amino-3-deoxy-alpha-D-allopyranosyl alpha-D-glucopyranoside, 3-amino-3-deoxy-alpha-D-glucopyranosyl alpha-D-glucopyranoside (3-trehalosamine) and 3-amino-3-deoxy-alpha-D-mannopyranosyl alpha-D-glucopyranoside. From the reductive amination of 3-ketosucrose, 3-amino-3-deoxy-alpha-D-allopyranosyl beta-D-fructofuranoside and 3-amino-3-deoxy-alpha-D-glucopyranosyl beta-D-fructofuranoside were obtained. The antibiotic and glycohydrolase inhibitory activities of these 3-amino-3-deoxy derivatives were determined.

Amination↗
PubMed1988

Selective inhibition of glycoprotein-processing enzymes. Differential inhibition of glucosidases I and II in cell culture.

In this study, we compared the effects of 2,6-dideoxy-2,6-imino-7-O-(beta-D-glucopyranosyl)-D-glycero-L-gulohep titol (MDL) to those of the glucosidase I inhibitor, castanospermine, on the purified processing enzymes glucosidases I and II. WE also compared the effects of these two inhibitors on glycoprotein processing in cell culture using influenza virus-infected Madin-Darby canine kidney cells as a model system. With the purified processing enzymes, castanospermine was a better inhibitor of glucosidase I than of glucosidase II, whereas MDL is more effective against glucosidase II than glucosidase I. In cell culture at the appropriate dose, MDL also preferentially affected glucosidase II. Thus, at 250 micrograms/ml MDL, the major [3H]glucose-labeled (or [3H]mannose-labeled) glycopeptide from the viral hemagglutinin was susceptible to endoglucosaminidase H, and the oligosaccharide liberated by this treatment was characterized as a Glc2Man7-9GlcNAc on the basis of size, resistance to digestion by glucosidase I (but sensitivity to glucosidase II), methylation analysis, and Smith degradation studies. These data indicate that at appropriate concentrations of MDL (250 micrograms/ml), one can selectively inhibit glucosidase II in Madin-Darby canine kidney cells. However, at higher concentrations of inhibitor (500 micrograms/ml), both enzymes are apparently affected. Since MDL did not greatly inhibit the synthesis of lipid-linked saccharides or the synthesis of protein or RNA, it should be a useful tool for studies on the biosynthesis and role of N-linked oligosaccharides in glycoprotein function.

Alkaloids↗
PubMed1984

[Antinutritional effect of phytohemagglutinins of Phaseolus vulgaris L].

The antinutritional effect caused by the ingestion of lectins from two Brazilian varieties of beans: Rico 23 and Jalo, was studied in rats. The two varieties were selected in a previous screening of toxicity in rats: one of them (Jalo) was lethal, and the other (Rico 23) was not, when injected intra-peritoneally. Different amounts of each one of the lectins were added to casein experimental diets and fed to rats. The amount of protein (casein) also varied from 5% to 20%. The addition to the diet of 1% lectins from the Jalo variety caused a growth depression, as well as a decrease in food efficiency ratio and serum glucose; also, it reduced the maltase and invertase activity of the intestinal mucosa. All these effects appeared when the protein contents in the rations were 5% or 10%. At the 20% level only a depression of the maltase activity was observed. Similar effects were shown by the lectins of the Rico 23 variety, but only when added in a higher (5%) percentage to the diet. The phosphatase and protease activity were not changed by any of the lectins. The inhibitor activity that occurred in vivo was not detected in vitro.

Animals↗