Table 2.

Kinetic properties of WT and mutant CaMs

CaMsKD values for Ca2+, μM
Kact for CaMKII, μM2kp of CaMKII, (sec−1)3
KD1KD2KD3KD4
WT CaM7.91.7358.90.040.96
CaM-CWT 251.650.064
CaM-NWT 283.3200.12
  • K D values for Ca2+ were calculated as described in Methods from the data in Fig. 3D with the CaLigator program (47) downloaded from www.bpc.lu.se/research/caligator. A model containing four Ca2+ sites was used for WT CaM, and one containing two Ca2+ sites was used for CaM-CWT and CaM-NWT. The concentration of WT CaM required for half-maximal rate of CaMKII autophosphorylation, K act, is taken from Meyer et al. (16). K act values for mutant CaMs were determined from the data in Fig. 4B. The intrinsic turnover rate of CaMKII autophosphorylation, k p, was determined from data in Fig. 5. Confidence intervals (95%) for k p values were 0.67–1.25 for WT CaM, 0.044–0.084 for CaM-CWT, and 0.079–0.16 for CaM-NWT.