Table I.

Summary of actin-activated ATPase data

1 mM EGTA100 mM Ca2+EGTA + 6 μM CaMCa2+ + 6 μM CaM
ConstructVmaxKmVmaxKmVmaxKmVmaxKm
sec−1μMsec−1μMsec−1μMsec−1μM
MD2IQ20.8 ± 5.1 (3)6.4 ± 2.7 (3)19.5 ± 11 (3)6.3 ± 1.2 (3)23.3 ± 5.7 (3)7.6 ± 2.3 (3)23.7 ± 6.4 (3)9.8 ± 3.3 (3)
dHMM9.7 ± 0.8 (3)2.7 ± 1.4 (3)13.6 ± 1.0 (3)3.0 ± 2.1 (3)12.7 (2)1.5 (2)17.3 (2)1.7 (2)
Long-dHMM6.5 (2)5.8 (2)6.5 (2)4.7 (2)10.6 ± 0.6 (3)3.0 ± 1.8 (3)16.5 ± 1.2 (3)1.5 ± 0.6 (3)
dFull2.3 ± 0.6 (4)7.7 ± 1.0 (4)8.7 ± 1.2 (4)4.2 ± 1.2 (4)2.18 ± 0.1 (3)5.1 ± 0.6 (3)16.0 ± 1.1 (3)1.4 ± 0.1 (3)
  • The number in parentheses indicates the number of ATPase assays performed, each done over a range of actin concentrations. Values are means ± SD, or an average when n = 2. Each value was measured on at least two independent preparations.