Table 1.

Kinetic parameters of ATPase activity in the absence and presence of chaperones or N-terminal HMBD and Cu-binding stoichiometry of each protein

Cu+ formVmax,* μmol/mg/hK1/2,* μMCu+/protein stoichiometry
ΔN-AtPAA1Cu+0.86 ± 0.040.27 ± 0.061.89 ± 0.15
Cu+-AtPCH12.62 ± 0.251.81 ± 0.63
Cu+-AtPAA1-HMBD1.61 ± 0.140.10 ± 0.06
Cu+-AtPAA2-HMBD−0.37 ± 0.27n.d.
Cu+-AtCCS0.07 ± 0.04n.d.
ΔN-AtPAA2Cu+0.86 ± 0.060.38 ± 0.122.17 ± 0.046
Cu+-AtPCH10.10 ± 0.03n.d.
Cu+-AtPAA1-HMBD0.10 ± 0.03n.d
Cu+-AtPAA2-HMBD−0.03 ± 0.05n.d.
Cu+-AtCCS1.27 ± 0.040.79 ± 0.06
AtPCH1Cu+1.07 ± 0.08
AtPAA1-HMBDCu+0.91 ± 0.21
AtPAA2-HMBDCu+0.91 ± 0.12
AtCCSCu+1.10 ± 0.22
  • n.d., not determined.

  • * Errors for Vmax and K1/2 are asymptotic SEs reported by the fitting software Kaleidagraph (Synergy).

  • Stoichiometry of Cu+ bound to ATPases or chaperones was estimated as moles Cu+/moles protein.