Fig. 2.

Time course assay showing the Mt-PrsA catalyzed formation of p[¹⁴C]Rpp from [¹⁴C]R5P and ATP. Assays contained Mt-PrsA, 50 mM Pi, 2 mM ATP supplemented with either 2 mM Mg²⁺, Mn²⁺ or Ca²⁺ as illustrated in (A), and in the presence of ADP at a final concentration of 2 mM in (B). Assays were incubated at 37°C, and aliquots were removed from the assay mix at 0, 10, 30 and 60 s and the reactions halted by quenching with the addition of formic acid. Samples were applied to a glass-backed PEI-cellulose TLC plate and developed in 0.85 M KH₂PO₄ (pH 3.4). The plate was inspected for radioactive spots relating to p[¹⁴C]Rpp and [¹⁴C]R5P by autoradiography through the exposure of TLCs to X-ray film (Kodak X-Omat).