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.

Partial purification of galactinol synthase from leaves of Cucurbita pepo

Abstract: An enzyme synthesizing galactinol, UDP-D-galactose:myo-inositol-1-α-D-galactosyl transferase (galactinol synthase), has been isolated and partially purified from mature leaves of Cucurbita pepo. The enzyme showed optimal activity between pH 7.5 and 8.0 and required Mn2+ and the presence throughout isolation, storage, and assay of a sulfhydryl protectant (β-mercaptoethanol). EDTA was completely inhibitory. From a range of metal ions only Mg2+ partially replaced Mn2+, while Co2+, Zn2+, Cu2+, and Ni2+ were inhibitory. The uridine nucleotides and UDP-glucose were from 40 to 80% inhibitory and probably constitute part of the in vivo control system. High concentrations of galactose, melibiose, and xylose were partially inhibitory. The enzyme appeared highly specific for myo-inositol and showed no ability for galactosyl transfer to any other naturally occurring sugar or sugar alcohol. Some reactivity was obtained with the isomeric scyllo-inositol but the product was not identified. A range of other sugar nucleot...

Production and characterization of α‐galactosidase from Aspergillus flavipes

Abstract: An extracellular α-galactosidase from the culture filtrate of Aspergillus flavipes grown on melibiose as a carbon source was partially purified by hydroxylapatite and diethylaminoethylcellulose chromatographies. Electrophoretic analysis showed protein bands corresponding to α-galactosidase and invertase activities. The optimum pH and temperature were determined as 4.5–5.0 and 45°C, respectively. The Km value for p-nitrophenyl-α-d-galactopyranoside was found to be 1.89 mm. The results reported in this study indicate that Aspergillus flavipes is indeed an active source of extracellular α-galactosidase. Copyright © 2003 John Wiley & Sons, Ltd.

Functional Characterization of a Eukaryotic Melibiose Transporter

Abstract: Pathogenic fungi drastically affect plant health and cause significant losses in crop yield and quality. In spite of their impact, little is known about the carbon sources used by these fungi in planta and about the fungal transporters importing sugars from the plant-fungus interface. Here, we report on the identification and characterization of MELIBIOSE TRANSPORTER1 (MBT1) from the hemibiotrophic fungus Colletotrichum graminicola (teleomorph Glomerella graminicola), the causal agent of leaf anthracnose and stalk rot disease in maize (Zea mays). Functional characterization of the MBT1 protein in baker’s yeast (Saccharomyces cerevisiae) expressing the MBT1 cDNA revealed that α-d-galactopyranosyl compounds such as melibiose, galactinol, and raffinose are substrates of MBT1, with melibiose most likely being the preferred substrate. α-d-Glucopyranosyl disaccharides like trehalose, isomaltose, or maltose are also accepted by MBT1, although with lower affinities. The MBT1 gene shows low and comparable expression levels in axenically grown C. graminicola and upon infection of maize leaves both during the initial biotrophic development of the fungus and during the subsequent necrotrophic phase. Despite these low levels of MBT1 expression, the MBT1 protein allows efficient growth of C. graminicola on melibiose as sole carbon source in axenic cultures. Although Δmbt1 mutants are unable to grow on melibiose, they do not show virulence defects on maize.

Factors regulating production of alpha-galactosidase from Bacillus sp. JF2

Abstract: Certain factors affecting the production of cell-associated alpha-galactosidase by Bacillus sp. JF2 were investigated. The intention was to maximize alpha-galactosidase activity of potential commercial application, by consecutive optimization of growth media and conditions. The highest alpha-galactosidase activity was obtained when grown on melibiose, whereas sucrose inhibited the production of alpha-galactosidase, alpha-Galactosidase production was optimally active at pH 7.5 and 55 degrees C. It was identified that a soy effluent stream could be used as the best carbon source for alpha-galactosidase by Bacillus sp. JF2.