Kinetics for NTP synthesizing activities by PPK1 and PPK2 from M. tuberculosis.

NTP synthesis assays were carried out following incubation of purified protein (5 µg/reaction for each protein) with 250 µM poly-P20 and different concentrations of ADP (12.5–800 µM for mPPK1 and 1–40 mM for mPPK2) or GDP (1–40 mM). Km and Vmax values were determined from non-linear regression analysis of Michaelis-Menten equation. For calculating kcat values, molecular masses of the recombinant mPPK1 and mPPK2 are considered as 86 kDa and 36 kDa respectively. Results are presented as Mean ± SD.