Modeling CICR in rat ventricular myocytes: voltage clamp studies

Table 4 Parameters used to model intracellular ion transport

Parameter	Definition	Value	References
$k_{12}^{P L B}$	rate of PLB_dp phosphorylation	6800 s^-1	[77]*
$k_{21}^{P L B}$	rate of PLB_p dephosphorylation	1000 s^-1	[77]*
K_cyt,serca	Maximal binding/release rate of Ca²⁺ from cytosol to SERCA	6250 s^-1	[77]*
K _serca,sr	Maximal binding/release rate of Ca²⁺ from SERCA to LSR	6.25 s^-1	[77]*
SERCA _tot	Total amount of SERCA	47.0 μM	[77]*
PSR	Phospholamban to SERCA ratio	1.0	[77]*
PKA _{ac t}	Relative regulatory activity of PKA	0.1	[77]^†
τ _tr	Time const. for transfer of Ca²⁺ from LSR to jSR	7.0 × 10^-3 s	[30]^‡
τ _Na	Time const. for transfer of Na⁺ from dyad to myoplasm	1.0 × 10^-3 s	[30]^‡
τ _Cs	Time const. for transfer of Cs⁺ from dyad to myoplasm	6.0 × 10^-3 s	[30]^‡
P _ryr	Permeability of the RyR channel	1.714 × 10^-7 μL · s^-1	[27, 28, 13]^‡
D _Ca	Diffusion constant for Ca²⁺ in the dyadic space	100.0 μm²s^-1	[119]*
N _h	Density of high-affinity Ca²⁺ binding sites	200.0 μM	[119]^‡
N _l	Density of low-affinity Ca²⁺ binding sites	16.0 μM	[119]^‡
K _l	Half-saturation value of low-affinity Ca²⁺ binding site	1100.0 μM	[119]*
K _h	Half-saturation value of high-affinity Ca²⁺ binding site	13.0 μM	[119]*
[Mg²⁺]_myo	Intracellular Mg²⁺ concentration	634 μM	[124]*
[fluo 3]_tot	total concentration of indicator dye	100.0 μM	Measured
$k_{f l u o 3}^{+}$	association rate of Ca²⁺ binding to dye fluo-3	80 μM ^-1 · s^-1	[125]*
$k_{f l u o 3}^{-}$	dissociation rate of Ca²⁺ binding to dye fluo-3	90 s^-1	[125]*

Table 4 Parameters used to model the intracellular ion transport I_cyt,serca, I_serca.sr, I_tr, I_RyR, and Ca²⁺ diffusion/buffering. Adopted (*), derived (†) or estimated (‡) from the cited sources.

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