Table 1.

Rate and equilibrium constants for TRAPP and nucleotide binding to Ypt1p.

Parameter	Value	Source
GDP
k+1	0.096 (±0.004) μM-1 s-1	mant-dGDP binding
	0.05 (±0.01) μM-1 s-1	mantGDP binding10
k-1	0.00012 (±0.00002) s-1	[H3]GDP Filter binding10
K1	1.2 (±0.2) nM	Ratio of rate constants
K3	4.8 (±1.2) μM	mant-GDP/mant-dGDP (Figure 1)
k+4A	2.4 (±0.1) μM-1 s-1	Linear fit (Figure 2)
	2.5 (±0.1) μM-1 s-1	Global fit (Figure 2)
k-4A	22.1 (±2.0) s-1	Linear fit (Figure 2)
	15.7 (±5.3) s-1	Global fit (Figure 2)
k+4B	20.7 (±2.2) s-1	Hyperbolic fit (Figure 2)
	11.7 (±12.0) s-1	Global fit (Figure 2)
k-4B	0.17 (±0.01) s-1	mantGDP/mant-dGDP (Figure 1)
K4A = (k-4A/k+4A)	9.2 (±0.9) μM	Ratio of rate constants
	6.3 (±2.1) μM	Ratio of rate constants (global fit)
K4B = (k-4B/k+4B)	0.01 (±0.001)	Ratio of rate constants
K4,overall	75 (±10) nM	Calculated using Eq. 5
K2	77 (±25) nM	Detailed balance of Scheme 1
GTP/GMPPNP
k+1	0.10 (±0.01) μM-1 s-1	mantGTP binding10
k-1	0.00005 s-1	GTP and mant-GMPPNP dissociation11
K1	0.5 (±0.1) nM	Ratio of rate constants
K3	8 (±2) μM	mant-GMPPNP (Figure 1)
k-4	0.095 (±0.017) s-1	mant-GMPPNP (Figure 1)
k+4	3.2 (±0.1) μM-1 s-1	mantGTP binding10
K4	30 (±5) nM	Ratio of rate constants
K2	133 (±48) nM	Detailed balance of Scheme 1