Cloning of two isoamylase genes, MeISA1 and MeISA2, from cassava (Manihot esculenta Crantz) tubers, accompanied by their co-expression in E. coli demonstrates a requirement for heteromeric complex formation to achieve debranching activity. Starch debranching enzyme (DBE) or isoamylase (ISA) (EC.
View Article and Find Full Text PDFThe degradation of transitory starch in the chloroplast to provide fuel for the plant during the night requires a suite of enzymes that generate a series of short chain linear glucans. However, glucans of less than four glucose units are no longer substrates for these enzymes, whereas export from the plastid is only possible in the form of either maltose or glucose. In order to make use of maltotriose, which would otherwise accumulate, disproportionating enzyme 1 (DPE1; a 4-α-glucanotransferase) converts two molecules of maltotriose to a molecule of maltopentaose, which can now be acted on by the degradative enzymes, and one molecule of glucose that can be exported.
View Article and Find Full Text PDF2-Deoxy-2-fluoro-d-glucose, 3-deoxy-3-fluoro-D-glucose and 6-deoxy-6-fluoro-D-glucose were converted into the corresponding maltose derivatives using Arabidopsis thaliana DPE2-mediated trans-glycosylation reaction with glycogen acting as a glucosyl donor. (19)F NMR spectroscopy proved to be a valuable tool for monitoring the progress of these reactions and to assess the nature of resulting oligomeric products.
View Article and Find Full Text PDFEndo-beta-N-acetylglucosaminidases are thought to be key enzymes in the catabolism of asparagine-linked oligosaccharides. However, little is known about the enzymes of this type in basidiomycetes. We investigated endo-beta-N-acetylglucosaminidases in basidiomycetes using fluorescence-labeled glycoasparagines as substrates.
View Article and Find Full Text PDFCalmodulin (CaM) proteins, members of the EF-hand family of Ca(2+)- binding proteins, represent important relays in plant calcium signals. Here, OsCam1-1 was isolated by PCR amplification from the rice genome. The gene contains an ORF of 450 base pairs with a single intron at the same position found in other plant Cam genes.
View Article and Find Full Text PDFBiosci Biotechnol Biochem
October 2007
A newly isolated strain, 38C-2-1, produced alkaline and thermotolerant alpha-amylases and was identified as Bacillus halodurans. The enzymes were purified to homogeneity and named alpha-amylase I and II. These showed molecular masses of 105 and 75 kDa respectively and showed maximal activities at 50-60 degrees C and pH 10-11, and 42 and 38% relative activities at 30 degrees C.
View Article and Find Full Text PDFGene encoding cyclodextrin glycosyltransferase (CGTase), from thermotolerant Paenibacillus sp. T16 isolated from hot spring area in northern Thailand, was cloned and expressed in E. coli (JM109).
View Article and Find Full Text PDFA thermoactive and thermostable levansucrase was purified from a newly isolated thermophilic Bacillus sp. from Thailand soil. The purification was achieved by alcohol precipitation, DEAE-Cellulose and gel filtration chromatographies.
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