Catalytic activities and kinetic parameters of enzymes involved in C5 sugar metabolism

Range Table - link
Organism Archaea Sulfolobus spp.
Reference Nunn CE, Johnsen U, Schonheit P, Fuhrer T, Sauer U, Hough DW, Danson MJ. Metabolism of pentose sugars in the hyperthermophilic archaea Sulfolobus solfataricus and Sulfolobus acidocaldarius. J Biol Chem. 2010 Aug 24, table 1PubMed ID20736170
Method To confirm the activities and substrate specificities of the enzymes in the proposed pathway for C5 sugar catabolism (Fig. 2), and to determine their kinetic parameters, the genes encoding the enzymes have been cloned from S. solfataricus and expressed in E. coli. In each case, heat-treatment of the cell extract gave recombinant enzyme that was of >90% purity, although in some cases a chromatography step was then carried out to achieve a homogeneous preparation. The data are recorded in Table 1 and are compared with those found with enzyme assays from cell extracts.
Comments In the current paper, researchers demonstrate that Sulfolobus possesses a C5-specific dehydratase that catalyses the dehydration of D-xylonate and L-arabinonate to 2-keto-3-deoxy-D-xylonate (KD-xylonate), and 2-keto-3-deoxy-L-arabinonate (KD-arabinonate), respectively, and the enzymes glycolaldehyde oxidoreductase and glyoxylate reductase to catalyse the conversion of glycolaldehyde to glycolate and then to glyoxylate, which enters the citric acid cycle via the action of malate synthase. See notes under table
Entered by Uri M
ID 105663