Kinase experiment:

The high-performance liquid chromatography (HPLC) analyses are carried out using a Fast Acid Column (100×7.8 mm) and a HPX-87H Ion Exclusion Column (300 mm×7.8 mm) in series with 2.5 mM H2SO4 in water as the mobile phase at a flow rate of 0.3 mL/min, at 55℃. This method enabled quantification of D-glucose, ethanol, glycerol, D-xylulose, Ribitol, and xylitol. D-ribose, D-ribulose, and D-arabitol coeluted on the Aminex HPX-87H column. The CarboPac MA-1 column of Dionex ICS-3000 is used to analyze representative culture supernatant samples for the presence of arabitol and xylitol. Samples are run at column temperature of 30℃ with 480 mM NaOH at flow rate 0.4 mL/min. The CarboPac MA-1 column separated D-arabitol from D-ribose and D-ribulose, but the alkaline conditions degraded D-ribulose interfering with the quantification of D-ribose.Yeast cells are disrupted with glass beads in 100 mM sodium phosphate buffer pH 7.0 containing phenylmethylsulfonyl fluoride and pepstatin A in final concentrations of 0.17 mg/mL and 0.01 mg/mL, respectively.The activity of NAD+-dependent Gdh2p is measured in a reaction buffer of 0.5 M triethanol amine pH 7.7 and 2 mM NADH. After addition of the cell lysate, the reaction is started by adding a mixture of α-ketoglutarate (100 mM) and NH4Cl (200 mM) to a final concentration of 2.4 mM and 4.9 mM, respectively. The GapB activity is measured. Shortly, the reaction mixture is 500 mM triethanol amine pH 7.8, 1 mM ATP, 2 mM MgCl2, 200 μM NADPH, and 10 μg/mL of phosphoglycerate kinase. 3-phosphoglycerate is added to a final concentration of 5 mM to start the reaction. Activity measurements are performed with a Cobas Mira Plus automated analyzer[2].

Ribitol is a crystalline pentose alcohol formed by the reduction of ribose. Enhancing the flux of D-glucose to the pentose phosphate pathway in Saccharomyces cerevisiae for the production of D-ribose and ribitol.

Ribitol is a reduced sugar[1]. Phosphoglucose isomerase-deficient (pgi1) strains of Saccharomyces cerevisiae are studied for the production of D-ribose and Ribitol from D-glucose via the intermediates of the pentose phosphate pathway. Overexpression of the gene encoding sugar phosphate phosphatase (DOG1) of S. cerevisiae is needed for the production of D-ribose and Ribitol. The engineered strains are compared for their ability to produce the PPP-derived 5-carbon compounds Ribitol and D-ribose from D-glucose[2].

References:
[1]. Praissman JL, et al. The functional O-mannose glycan on α-dystroglycan contains a phospho-Ribitol primed for matriglycan addition. Elife. 2016 Apr 29;5. pii: e14473.
[2]. Toivari MH, et al. Enhancing the flux of D-glucose to the pentose phosphate pathway in Saccharomyces cerevisiae for the production of D-ribose and ribitol. Appl Microbiol Biotechnol. 2010 Jan;85(3):731-9.