FIG. 2.

GTPase and ATPase activities of His₆-BCTD at 37°C. (A) Copurification of His₆-BCTD with nucleotide hydrolysis activities. The His₆-BCTD preparation was fractionated on a calibrated FPLC Superdex-200 gel filtration column (Pharmacia; 0.5 ml min⁻¹) in 50 mM Tris-HCl (pH 7.6)–20 mM KCl–20 mM NH₄Cl–1 mM DTT, and fractions of 40 μl were assayed for activity. Size standards included carbonic anhydrase (29 kDa [29KD]), bovine serum albumin (66 kDa), and alcohol dehydrogenase (150 kDa). (B) Substrate concentration titration of GTP and ATP hydrolysis of His₆-BCTD at 37°C. (C) Lineweaver-Burk plot of the GTPase and ATPase activities.