Skip to main content
. Author manuscript; available in PMC: 2014 Aug 23.
Published in final edited form as: J Mol Biol. 2013 May 23;425(16):10.1016/j.jmb.2013.05.013. doi: 10.1016/j.jmb.2013.05.013

Fig. 2.

Fig. 2

Kinetic analysis of SRSF1 phosphorylation by CLK1. (a) Viscometric experiments. The steady-state kinetic parameters kcat with varying ATP (○) or SRSF1 (△) and kcat/Km with varying ATP (●) or SRSF1 (▲) are plotted as relative values in the absence and presence of varying sucrose concentrations versus relative solvent viscosity. Broken lines represent theoretical slope values of 0 and 1. (b) Rapid quench flow experiment. Final concentrations of CLK1, SRSF1 and 32P-ATP are 0.25 μM, 0.5 μM and 100 μM. Production of phosphoproduct normalized to the total CLK1 concentration ([P]/[E]) is fit to a linear function with a slope of 0.08 s−1. (c) Competition experiments. Fixed amounts of SR(ΔRRM1) (50 nM) and 32P-ATP (50 μM) are added to CLK1 (10 nM) or SRPK1 (1 nM) with varying amounts of SRSF1 (competitor), and the reactions are stopped and run on SDS-PAGE. The relative velocities for SR(ΔRRM1) phosphorylation are plotted as a function of total SRSF1, and the appKI values are listed in Table 1.