FIGURE 8.

Enzyme activation by human and Pf CaM. Activation ability was tested with CaN (A), PDE (B), and MLCK (C). Activity is shown in arbitrary units (A), normalized to the values measured in the absence of CaM (B), or normalized between zero (for the inactive enzyme) and maximal values in the presence of saturating amounts of CaM (C), respectively. In the case of Pf CaM, PDE activity was also measured in the presence of TFP or melittin (panel B, last two columns). Parameters obtained from fitting to sigmoidal dose‐response curves are A) CaN vs human CaM: EC₅₀ = 0.67 ± 0.04 nmol/L, activation by CaM: 2.34‐fold, and CaN vs Pf CaM: EC₅₀ = 0.97 ± 0.10 nmol/L, activation by CaM: 2.07‐fold; C) MLCK vs human CaM: EC₅₀ = 5.6 ± 0.52 nmol/L, and MLCK vs Pf CaM: EC₅₀ = 16.7 ± 2.8 nmol/L