The dependence of speed, specificity, and selectivity on the phosphorylation rate kp (in s−1). (a) shows the speed for N = 6, koff = 0.10 s−1, and kon = 10 s−1; (b) shows the sensitivity for N = 6, koff = 0.10 s−1, and kon = 10 s−1; and (c) shows the specificity for N = 6, = 0.1 s−1, = 1 s−1, = 1 s−1, and = 1000 s−1. To see this figure in color, go online.