FIGURE 9.

Effect of nucleotides on time course of reactions catalyzed by IcmF. A, time course of the isobutyryl-CoA mutase reaction catalyzed by Gk IcmF at 37 °C. The assay mixture in Buffer A with 10 mm MgCl₂ contained 40 μg of holo-IcmF, 100 μm AdoCbl, 1.5 mm isobutyryl-CoA, and either no nucleotides (black circles), 6 mm ATP (triangles), or 3 mm GTP (open circles). B, time course of the isovaleryl-CoA mutase reaction catalyzed by Gk IcmF. The reaction mixture in Buffer A with 15 mm MgCl₂ contained 2500 μg of IcmF, 100 μm AdoCbl, and 1.5 mm isovaleryl-CoA with (white circles) or without 5 mm GTP (black circles) at 37 °C. Aliquots of the reactions were removed at different time points and analyzed by GC as described under “Experimental Procedures.” Data represent the average of three independent experiments. The data represent the mean ± S.D. of three independent experiments.