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Table 1 Description and initial ranges for the varied Niederer-model parameters

From: Insight into model mechanisms through automatic parameter fitting: a new methodological framework for model development

Parameter Description Minimum value Maximum value Default value
Ca 50ref Calcium sensitivity at resting sarcomere length (mM) 0.3e-3 0.8e-3 0.3e-3
k refoff Unbinding rate of Ca from TnC in the absence of tension (ms-1) 0 0.80 0.2
k on Binding rate of Ca to TnC (μM-1 s-1) 0 400 100
n r Relaxation parameter 2 4 3
β 0 Magnitude of length-dependent activation effects 1 5 4.9
β 1 Magnitude of filament overlap effects -8 0 -4
γ Effect of tension on the unbinding rate of Ca from TnC 2 100 2
nH Hill coefficient in the steady-state force-pCa curve 4 9 5
T ref Reference tension (kPa) 100 140 100
α 0 Monoexponential activation rate seen in caged Ca experiments (ms-1) 0 0.048 0.008
α r1 Slow relaxation rate (ms-1) 0 0.012 0.002
α r2 Fast relaxation rate (ms-1) 0 0.0105 0.00175
K z Relaxation parameter 0.1 0.2 0.15