Melibiose

About: Melibiose is a research topic. Over the lifetime, 1002 publications have been published within this topic receiving 27300 citations. The topic is also known as: Melibiose.

NMR studies on the interaction of sugars with the C-terminal domain of an R-type lectin from the earthworm Lumbricus terrestris.

Abstract: The R-type lectin EW29, isolated from the earthworm Lumbricus terrestris, consists of two homologous domains (14 500 Da) showing 27% identity with each other. The C-terminal domain (Ch; C-half) of EW29 (EW29Ch) has two sugar-binding sites in subdomains α and γ, and the protein uses these sugar-binding sites for its function as a single-domain-type hemagglutinin. In order to determine the sugar-binding ability and specificity for each of the two sugar-binding sites in EW29Ch, ligand-induced chemical-shift changes in EW29Ch were monitored using 1H–15N HSQC spectra as a function of increasing concentrations of lactose, melibiose, d-galactose, methyl α-d-galactopyranoside and methyl β-d-galactopyranoside. Shift perturbation patterns for well-resolved resonances confirmed that all of these sugars associated independently with the two sugar-binding sites of EW29Ch. NMR titration experiments showed that the sugar-binding site in subdomain α had a slow or intermediate exchange regime on the chemical-shift timescale (Kd = 10−2 to 10−1 mm), whereas that in subdomain γ had a fast exchange regime for these sugars (Kd = 2–6 mm). Thus, our results suggest that the two sugar-binding sites of EW29Ch in the same molecule retain its hemagglutinating activity, but this activity is 10-fold lower than that of the whole protein because EW29Ch has two sugar-binding sites in the same molecule, one of which has a weak binding mode.

Lactobacilli isolated from French saucisson (taxonomic study).

Abstract: 190 Lactobacilli strains originating from saucisson produced in France, were isolated. The use of numerical taxonomy enabled 6 representative taxa to be established, defined by average biochemical profiles, differing greatly from those of Lactobacilli from dairy origins. Two groups of tests seem to be of particular interest in order to characterize these strains: 1. Fermentaion of ribose: positive, Arginine dihydrolase: positive, Gas production: negative. 2. Fermentation of melibiose: positive, Fermentation of raffinose: negative.

Alpha‐galactosidase of germinating seeds of cassia sericea sw.

Abstract: Germinating seeds of Cassia sericea Sw contain two molecular forms of α-galactosidase which were partially purified and characterized Both enzyme forms had an optimum pH of 50 and an optimum temperature of 50 °C Km values for the substrate p-nitrophenyl-α-D-galactoside (PNPG) were 091 mM and 105 mM for the two forms, and substrate inhibition was observed at high concentrations of PNPG The two forms of the enzyme had molecular weights of 46,000 and 33,000 by gel filtration The enzyme forms were inhibited completely by Ag+, Cu2+ and Hg2+ ions and by p-chloromercuribenzoate showing that thiol groups are probably involved in catalysis Both α-galactosidases hydrolyzed melibiose and raffinose, although hydrolysis of stachyose could not be detected The enzyme may find potential use in the food industry to hydrolyze flatulence-causing sugars in processed foods and in production of sucrose from high-raffinose sugar beets That the source (C sericea seeds) of the enzyme is inexpensive provides an added advantage over use of cultivated legumes as a source of α-galactosidase

Characteristic Features of an ${\alpha}-Galactosidase$ from Penicillium purpurogenum

Abstract: A galactohydrolase; EC 3.2.1.22) was purified from the culture filtrate of Penicillium purpurogenum by DEAE-cellulose column chromatography, gel filtration of Bio gel p-l00, and subsequent SP-Sephadex C-25 chromatography. The final preparation thus obtained showed a single band on polyacrylamide disc-gel and SDS-polyacrylamide gel electrophoresis. The molecular weight and isoelectric point were determined to be 63,000 and pH 4.0 by SDS-polyacrylamide gel electrophoresis and isoelectric focusing, respectively. The galactosidase exhibited maximum activity at pH 4.5 and , and was stable between pH 2 and 5, and also stable up to . The enzyme activity was not affected considerably by treatment with other metal compounds except mercuric chloride and silver nitrate. Copra galactomannan was finally hydrolyzed to galactose, mannose and mannobiose through the sequential actions of the purified galactosidase and mannanase from the same strain. The enzyme hydrolyzed melibiose and raffinose, but not lactose.

Melibiose, a Nondigestible Disaccharide, Promotes Absorption of Quercetin Glycosides in Rat Small Intestine

Abstract: We demonstrated that melibiose, a nondigestible disaccharide composed of galactose and glucose with α-1,6 glycoside linkage, promotes the absorption of water-soluble quercetin glycosides in ligated small intestinal loop of anesthetized rats Water-soluble quercetin glycoside, a quercetin-3-O-glucoside mixture (Q3GM), includes quercetin-3-O-glucoside (Q3G, 319%), mono (212%) and di (171%), glucose adducts with α-1,4 linkages After instillation of Q3GM into the intestinal loop with or without melibiose, the plasma concentration of quercetin derivatives in the portal blood was considerably higher in the melibiose group at 60 min Furthermore, we evaluated the hydrolytic rate of Q3G by the mucosal homogenate of the small intestine with six different disaccharides Melibiose and isomaltose, which have α-1,6 glycoside linkage, were found to promote Q3G hydrolysis to aglycone These results suggest that melibiose promotes quercetin glycoside absorption in rats by increasing glycoside hydrolysis in the intest