Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.26 (invertase)
 4,927 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mannose-specific binding sites for horseradish peroxidase (HRP) were studied in fixed sections of various tissues by a method reported previously. Liver sinusoidal cells, mast cells of lymph nodes, and alveolar macrophages of the lung and skin fibroblasts were main cell types showing mannose-specific binding of HRP. Macrophages, fibroblasts, and mast cells in the connective tissue of other organs also showed the reaction. However, macrophages of the spleen, and cultured 3T3 cells and L-cells did not give the reaction. The specificities of the binding reaction were studied by determining the approximate concentrations of competing sugars that suppressed the specific binding of HRP. It was found that the endogenous lectins in macrophages, fibroblasts, mast cells, and liver sinusoidal cells showed similar specificities toward various carbohydrates. D-Mannose and L-fucose had the highest affinity toward the lectins (competing ability for the binding of HRP). D-Mannose-6-phosphate, N-acetyl-D-glucosamine, D-glucose, D-ribose, and D-arabinose showed intermediate affinity, whereas D-xylose and D-galactose showed low affinity. Polymerized mannose in mannan and glycoproteins rich in mannose groups (invertase and ribonuclease B) showed much higher affinity to the binding sites than free mannose.
 ...
PMID:Mannose-specific binding sites for horseradish peroxidase in various cells of the rat. 683 41

Oral immunization with gliadin (GLI) can induce immunoglobulin A mesangial deposits (IgA nephropathy [IgAN]) in mice. A role for GLI in human IgAN has been inferred from an association with celiac disease, increased serum anti-GLI IgA in patients with IgAN, and benefit from a gluten-free diet observed in some IgAN patients. These effects might be due to the antigenic or lectinic properties of GLI. The aim of our study was to investigate whether GLI binding to glycosylated residues (ie, lectinic activity) favors binding of GLI to cultured rat mesangial cells, bridging IgA macromolecules. We also sought to determine whether GLI binding alters mesangial cell function. Gliadin binds to rat mesangial cells in the third and fourth passages, as determined by immunofluorescence. Gliadin binding is inhibited by co-incubation with 1 mol/L N-acetyl-D-glucosamine and 1 mol/L alpha-D-mannose, sugars competitive for this lectinic bond. Quantification by biotinylated GLI revealed a significant dose-dependent binding of GLI (P < 0.001) inhibited by N-acetyl-D-glucosamine (P < 0.05). Some saccharolytic enzymes, like invertase, modify the cell surface to decrease GLI binding (P < 0.02). In addition, GLI promoted the binding of purified mouse polymeric IgA to mesangial cells. The binding of GLI to mesangial cells modulates arachidonic acid metabolism by cultured mesangial cells, significantly inhibiting prostaglandin E2 production (P < 0.02), increasing synthesis of thromboxane B2 (P < 0.01) and tumor necrosis factor (P < 0.001), but not interleukin-1 beta. These responses were abrogated by co-incubation with N-acetyl-D-glucosamine and/or pretreatment with invertase. Non-immune binding of an environmental alimentary lectin, GLI, to mesangial cells in culture might favor the binding of IgA and IgAIC to mesangial cells, enhancing both IgA mesangial trapping and in situ IgA deposit formation. This could occur via GLI-specific antibodies or by virtue of the binding of nonspecific IgA on a lectinic basis, or both. Moreover, related changes in eicosanoid synthesis might stimulate mesangial cell growth and mesangial matrix production, together with mesangial cell contraction, contributing to the pathogenesis of IgAN.
 ...
PMID:Functional consequences of the binding of gliadin to cultured rat mesangial cells: bridging immunoglobulin A to cells and modulation of eicosanoid synthesis and altered cytokine production. 831 Oct 90

We constructed a system for the expression and secretion of mature hen lysozyme by yeast using an intermediate "secretion-signal cassette" vector, pKP1700, containing the yeast invertase signal sequence and an expression vector, pAM82, for secretion and maturation of the enzyme. Using this system, mutants of hen lysozyme were produced and the catalytic mechanism in hen lysozyme was definitely confirmed. The hydrolytic activity of D52A as to substrate (NAG)6 at pH 5.0 was obviously decreased to one-four hundredth of that of the wild type. The acidic limb of the pH-activity profile observed for the wild-type was not observed for D52A, and the pKa of Glu 35 on the alkaline limb was seen for both enzymes. Moreover, no structural change was detected on X-ray analysis of D52A. Therefore, we confirmed that dissociated Asp 52 assists catalysis by producing an electrostatic field and by stabilizing the oxocarbonium ion intermediate in the dissociated form.
 ...
PMID:A mutation study of catalytic residue Asp 52 in hen egg lysozyme. 890 88

Bioskin is a natural product produced by a mixed culture of Acetobacter xylinum, Saccharomyces cerevisiae and S. pombe cultured on media containing sucrose. It is of fibrillar nature able to retain some proteins, such as cytochrome c, by adsorption, and mainly composed of glucosamine and N-acetyl-D-glucosamine. This makes it possible that, at an adequate pH value, proteins charged as polyanionic molecules, such as catalase, can be retained by ionic adsorption using the positively charged amino groups of the matrix. In addition, bioskin can also be used as an affinity matrix to retain glycoproteins able to perform specific affinity reactions with the amino sugars of the matrix, such as invertase, fetuin or ovalbumin. Its possible use as a chromatographic support is discussed.
 ...
PMID:Bioskin as an affinity matrix for the separation of glycoproteins. 1140 92