b a ckground: the role of lectins is important in interaction between pathogens and mosquito vectors. this study was performed to identify agglutinin activities of protein molecules on the midgut of culex pipiens . m e t hods: c u lex pipiens was reared in insectray condition and the midguts of males and females (blood fed and un- fed) were dissected separately in tris-hcl buffer. the extracts ...

1. Under normal assay conditions the N-acetyl-D-glucosamine kinases from rat liver and kidney show a pH-dependent lag phase before reaching a steady state, which is probably due to reversible dissociation of the dimeric enzyme. 2. The enzyme catalyses the phosphorylation of N-acetyl-D-glucosamine, N-acetyl-D-mannosamine and D-glucose at pH 7.5, with apparent Km values of 0.06, 0.95 and 600 mM r...

The Bidder's organ and ovary of the Brazilian toad Bufo ictericus were studied by light microscopy, using hematoxylin-eosin (HE) and periodic acid Schiff (PAS) staining. The expression and distribution of carbohydrate moieties was analyzed by lectin histochemistry, using 8 lectins with different carbohydrate specificities: Ulex europaeus (UEA I), Lens culinaris (LCA), Erythrina cristagalli (ECA...

The properties of an N-acetyl-d-glucosamine-transport system have been studied by following the intracellular accumulation of methyl 2-acetamido-2-deoxy-alpha-d-[1-(14)C]glucoside by Escherichia coli. The same analogue was used to assay phosphoenolpyruvate phosphotransferase activity of toluene-treated cells. Transport and phosphorylation are induced by growth on d-glucosamine or N-acetyl-d-glu...

niosomes are non-ionic surfactant vesicles that have potential applications in the delivery of hydrophilic and hydrophobic drugs. the topical form of n-acetyl glucosamine (nag) recently has been considered in the treatment of hyperpigmentation disorders due to its inhibitory effect on thyrosinase enzymes in melanocytes. to improve nag penetration into the skin we formulated the drug in niosomes...

Cellobiose phosphorylase (EC 2.4.1.20, CBP) catalyzes the reversible phosphorolysis of cellobiose to α-D-glucose 1-phosphate (Glc1P) and d-glucose. Cys485, Tyr648, and Glu653 of CBP from Ruminococcus albus, situated at the +1 subsite, were mutated to modulate acceptor specificity. C485A, Y648F, and Y648V were active enough for analysis. Their acceptor specificities were compared with the wild t...

A partially purified enzyme (120-fold) from Leuconostoc mesenteroides catalyzed the reversible N-acetylation of d-glucosamine-6-phosphate. Coenzyme A was not required and inhibited the reaction rate. Neither d-glucosamine nor N-acetyl-d-glucosamine served as a substrate for the reversible reaction. The enzyme preparation retained 50% of its original activity after 5 min at 100 C. The K(m) for a...