TABLE 1.

Comparison of models describing the effect of soluble lipid on DEGR-factor X_a fluorescence intensity

Lipid	Model #sites/Eq.	Parameters*	100 nM DEGR-Xa 3 mM Ca	100 nM DEGR-Xa 5 mM Ca	1 nM DEGR-Xa 5 mM Ca	150 nM DEGR-Xa 5 mM Ca
C6PS	Sequential	kd1	90†	90†	110 ± 15	90†
	2/A4	kd12	222 ± 34	682 ± 185	1420‡	255 ± 22
		ΔRsat,1	0.06 ± 0.02	0.02‡	−0.19 ± 0.01	0.04 ± 0.01
		ΔRsat,12	−0.28 ± 0.01	−0.41 ± 0.04	−0.060‡	−0.36 ± 0.01
		R2/σ	0.997/0.0042	0.997/0.0053	0.993/0.0042	0.999/0.0036
	Dimer/Seq.	kd1	90†	90†	ND	90†
	2/A6	kd12	208 ± 39	435 ± 137		185 ± 26
		ΔRsat,1	−0.14‡	−0.11‡		−0.15‡
		ΔRsat,12	−0.30 ± 0.01	−0.37 ± 0.04		−0.35 ± 0.01
		ΔRsat,3	0.16‡	0.13‡		0.16‡
		R2/σ	0.998/0.0036	0.996/0.0044		0.999/0.0031
C6PG	Sequential	kd1	200†	200†	NA	NA
	2/A4	kd12	1130 ± 270	750 ± 110
		ΔRsat,1§	0.013‡	0.023 ± 0.008
		ΔRsat,12§	−0.18 ± 0.02	−0.16 ± 0.01
		R2/σ	0.988/0.004	0.994/0.0015

^*Units of dissociation constants are μM. ΔR_sat values are fluorescence quantum yield differences between the lipid-bound state and the lipid-free state of DEGR-X_a relative to the quantum yield of the lipid-free state.

^†This value fixed based on titration of activity for C6PS or results ±Ca²⁺ for C6PG.

^‡A t-test on this parameter produced a P > 0.05%, where P is the probability of being wrong in concluding that the parameter is zero. This indicates that this parameter value is ill determined.

^§These parameter values were constrained such that ΔR_sat,1 > 0, ΔR_sat,12 < 0.

ND (not determined).

NA (not applicable) means that these data did not support this analysis.