Table II. Compilation of the kinetic constants of inhibition by 1 mM intracellular MTSET in the closed and open state.
Position | Rate of inhibition in the closed state (mM–1 s –1) | Rate of inhibition in the open state (mM–1 s–1) |
---|---|---|
74 | 0.08 ± 0.055 | 0.09 ± 0.031 |
72 | 0.06 ± 0.075 | 0.17 ± 0.072 |
71 | 0.08 ± 0.03 | 0.36 ± 0.17 |
69 | 0.26 ± 0.037 | 0.12 ± 0.05 |
68 | 0.044 ± 0.011 | 0.099 ± 0.027 |
Kinetic constants were determined as described in Materials and methods, using 1-min-spaced pulses of 30 µM FMRF-amide for determinations in the closed state and continuous FMRF-amide application for determinations in the open state. Note the differences of accessibility between the closed and open states from position 69 to 72, showing that this region of the channel is involved in the gating mechanism.