Table Of Contents

These are "rules of thumb" and not absolute. However, if K d and n are unknown, a best
guess should provide enough data to fine-tune the parameters. An analysis of the data from the
run will show the average peak size, approximate n, and a better estimate of K d . Either the
concentrations or the injection sizes should be adjusted so that the large initial peaks are ~1 - 4
µCal/second in height. The peak height is roughly linearly proportional to each concentration
and the injection size. The refined estimate of K d allows for an adjustment of the cell and
syringe concentrations.
As an example, assume we have an enzyme in the cell with a K d of 0.000001. The
concentration of enzyme should therefore be 10 * K d = 0.00001 M or 10 µM. Since this is a
reasonably average K d , no further adjustment is required. Assuming a stoichiometry of 1, the
concentration of inhibitor in the 40 µl syringe should be 10 - 15-fold higher than the
concentration of the enzyme in the cell, or 10 µM * 10 = 100 µM to 10 µM * 15 = 150 µM.
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