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Updated: Mar 1, 2026
Author Spotlight: Integrating Biochemical Functions of β-Glucanases and Peroxidase Enzymes in Wheat-RWA Interaction
Published on: July 26, 2024
Photometric assay of maltose and maltose-forming enzyme activity by using 4-alpha-glucanotransferase (DPE2) from
Julia Smirnova1, Alisdair R Fernie2, Christian M T Spahn3
1Institute for Biochemistry and Biology, Department of Plant Physiology, University of Potsdam, Building 20, Karl-Liebknecht-Str. 20, 14461 Potsdam, Germany; Institute of Biophysics and Medical Physics of the Charité, Universitätsmedizin Berlin, Campus Berlin Mitte, 10117 Berlin, Germany; Max-Planck-Institute of Molecular Plant Physiology, Department 1 (Willmitzer), Am Mühlenberg 1, 14476 Potsdam-Golm, Germany.
Abstract:
Maltose frequently occurs as intermediate of the central carbon metabolism of prokaryotic and eukaryotic cells. Various mutants possess elevated maltose levels. Maltose exists as two anomers, (α- and β-form) which are rapidly interconverted without requiring enzyme-mediated catalysis. As maltose is often abundant together with other oligoglucans, selective quantification is essential. In this communication, we present a photometric maltose assay using 4-alpha-glucanotransferase (AtDPE2) from Arabidopsis thaliana. Under in vitro conditions, AtDPE2 utilizes maltose as glucosyl donor and glycogen as acceptor releasing the other hexosyl unit as free glucose which is photometrically quantified following enzymatic phosphorylation and oxidation. Under the conditions used, DPE2 does not noticeably react with other di- or oligosaccharides. Selectivity compares favorably with that of maltase frequently used in maltose assays. Reducing end interconversion of the two maltose anomers is in rapid equilibrium and, therefore, the novel assay measures total maltose contents. Furthermore, an AtDPE2-based continuous photometric assay is presented which allows to quantify β-amylase activity and was found to be superior to a conventional test. Finally, the AtDPE2-based maltose assay was used to quantify leaf maltose contents of both Arabidopsis wild type and AtDPE2-deficient plants throughout the light-dark cycle. These data are presented together with assimilatory starch levels.
