|Content:||500 Units at 60oC|
|Formulation:||In 3.2 M ammonium sulphate|
|Stability:||> 4 years at 4oC|
|Concentration:||Supplied at ~ 1,000 U/mL|
|Expression:||Recombinant from Yersinia enterocolitica|
|Specificity:||Hydrolysis of pectic acid from the non-reducing end, releasing digalacturonate.|
|Specific Activity:||~ 80 U/mg protein (60oC, pH 6.0 on Polygalacturonic Acid)|
|Unit Definition:||One Unit of exo-polygalacturonase activity is defined as the amount of enzyme required to release one µmole of reducing-sugar equivalents per minute from Polygalacturonic Acid (10 mg/mL) in potassium phosphate buffer (100 mM), pH 6.0.|
|Application examples:||For use in research.|
Characterization of a Novel Thermophilic Endopolygalacturonase Produced by Bacillus licheniformis IEB-8.
Hadri, S. H., Asad, M. J., Hyder, M. Z., Naqvi, S. M. S., Mukhtar, T., Zafar, M., Shah, S. H., Mehmood, R. T. & Wu, J. D. (2019). BioResources, 14(2), 2873-2884.
Endopolygalacturonases characterized until now have either low working temperatures, working pH in acidic range, high Michaelis-Menten constant (Km), or a high production cost. These characteristics are a hurdle in the industrial applications of these endopolygalacturonases. The purpose of this work was to characterize a novel endopolygalacturonase produced by Bacillus licheniformis IEB-8. Phylogenetic analysis of Bacillus licheniformis IEB-8 showed that the isolate was unique. Citrus peels were used as the only nutrient source for the growth of Bacillus licheniformis IEB-8, allowing a cheap production of endopolygalacturonase. All the synthetic carbon sources showed a negative impact on the production of endopolygalacturonase, while ammonium sulfate enhanced its production. Among different metal ions, Zn+2 showed a negative effect while Mg+2 and Ca+2 did not have any significant effect on the endopolygalacturonase activity. A Lineweaver-Burk plot was prepared for the characterization of the kinetic parameters including Km and Vmax, which were 0.45 mg/mL and 285.7 µM/min, respectively. A comprehensive comparison of the endopolygalacturonase from this study with the available literature indicated that it is better than the reported and commercially available endopolygalacturonases in having the optimum working temperature of 55°C, a low Km of 0.57 mg/mL, and pH of 7 to 8, which indicated its novelty.Hide Abstract
Carter, R., Woolfenden, H., Baillie, A., Amsbury, S., Carroll, S., Healicon, E., Sovatzoglou, S., Braybrook, S., Gray, J. E., Hobbs, J., Morris, R. J. & Morris, R. J. (2017). Current Biology, 27(19), 2974-2983.
It has long been accepted that differential radial thickening of guard cells plays an important role in the turgor-driven shape changes required for stomatal pore opening to occur. This textbook description derives from an original interpretation of structure rather than measurement of mechanical properties. Here we show, using atomic force microscopy, that although mature guard cells display a radial gradient of stiffness, this is not present in immature guard cells, yet young stomata show a normal opening response. Finite element modeling supports the experimental observation that radial stiffening plays a very limited role in stomatal opening. In addition, our analysis reveals an unexpected stiffening of the polar regions of the stomata complexes, both in Arabidopsis and other plants, suggesting a widespread occurrence. Combined experimental data (analysis of guard cell wall epitopes and treatment of tissue with cell wall digesting enzymes, coupled with bioassay of guard cell function) plus modeling lead us to propose that polar stiffening reflects a mechanical, pectin-based pinning down of the guard cell ends, which restricts increase of stomatal complex length during opening. This is predicted to lead to an improved response sensitivity of stomatal aperture movement with respect to change of turgor pressure. Our results provide new insight into the mechanics of stomatal function, both negating an established view of the importance of radial thickening and providing evidence for a significant role for polar stiffening. Improved stomatal performance via altered cell-wall-mediated mechanics is likely to be of evolutionary and agronomic significance.Hide Abstract
Abbott, D. W. & Boraston, A., B. (2007). Journal of Molecular Biology, 368(5), 1215-1222.
Family 28 glycoside hydrolases (polygalacturonases) are found in organisms across the plant, fungal and bacterial kingdoms, where they are central to diverse biological functions such as fruit ripening, biomass recycling and plant pathogenesis. The structures of several polygalacturonases have been reported; however, all of these enzymes utilize an endo-mode of digestion, which generates a spectrum of oligosaccharide products with varying degrees of polymerization. The structure of a complementary exo-acting polygalacturonase and an accompanying explanation of the molecular determinants for its specialized activity have been noticeably lacking. We present the structure of an exopolygalacturonase from Yersinia enterocolitica, YeGH28 in a native form (solved to 2.19 A resolution) and a digalacturonic acid product complex (solved to 2.10 A resolution). The activity of YeGH28 is due to inserted stretches of amino acid residues that transform the active site from the open-ended channel observed in the endopolygalacturonases to a closed pocket that restricts the enzyme to the exclusive attack of the non-reducing end of oligogalacturonide substrates. In addition, YeGH28 possesses a fused FN3 domain with unknown function, the first such structure described in pectin active enzymes.Hide Abstract