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. 2016 May 19;7:11534. doi: 10.1038/ncomms11534

Figure 1. ISPD is a CDP-ribitol pyrophosphorylase.

Figure 1

(a) CDP pyrophosphorylase reaction. (b) Activity of ISPD on CTP and D-ribitol-5-P. ISPD was incubated with the indicated concentrations of D-ribitol-5-P and 1 mM CTP for 30 min at 37 °C; CDP-ribitol was measured by HPLC. Curves were fitted to Michaelis–Menten kinetics (dotted line) and negative cooperativity (Hill coefficient=0.2; plain line). Means±s.e.m. of three independent experiments are shown. (c) Activity of ISPD on different pentose-phosphates and on the following pentitol-phosphates generated by borohydride reduction of pent(ul)ose-5-P: D-ribitol-5-P (reduction of D-ribose-5-P), D-arabitol-5-P (reduction of D-arabinose-5-P), D-ribitol-5-P and D-arabitol-5-P in equal amounts (reduction of D-ribulose-5-P), and equal amounts of D-xylitol-5-P and D-lyxitol-5-P (reduction of D-xylulose-5-P). Related structures are shown in Supplementary Fig. 1b. Activities were assessed in the presence of 1 mM CTP by measuring the product formation by HPLC. No more than 40% of the pent(ul)ose/pentitol-5-P was consumed at the end of the reaction. Means±s.d. (n=3) are shown. Three independent experiments were performed.