TABLE 2.
Summary of pCa50 of Ca2+ affinity or Ca2+ sensitivity measured by various experimental assays at different levels of complexity of the thin filament
TnC | pCa50 |
||||
---|---|---|---|---|---|
cTn | TF | ATPase 100% | ATPase 50%a | Skinned fiberb | |
WT | 6.69 ± 0.01 | 6.13 ± 0.02 | 5.69 ± 0.05 | 5.68 ± 0.02 | 5.66 ± 0.01 |
A8V | 6.58 ± 0.01c | 6.27 ± 0.02c | 6.20 ± 0.03c | 5.87 ± 0.03c | 6.02 ± 0.01c |
E134D | 6.69 ± 0.01 | 6.11 ± 0.02 | 5.72 ± 0.03 | 5.66 ± 0.04 | 5.68 ± 0.01 |
D145E | 6.81 ± 0.01c | 6.21 ± 0.02c | 5.94 ± 0.03c | 5.90 ± 0.02c | 5.90 ± 0.01c |
C84S | 6.77 ± 0.01 | NDd | ND | ND | ND |
C84Y | 6.76 ± 0.01 | ND | 6.25 ± 0.03c | 6.20 ± 0.03 | 5.93 ± 0.01c |
a WT in ATPase 50% was measured at 100% ratio and compared with the mutants at a 50% ratio.
b Skinned fiber values were obtained from Ref. (9).
cp < 0.05 compared with their respective WT.
d ND, not determined.