Table 1.

Sterol loading parameters of elicitins

Elicitin	N (mol/mol)	Cb (μM)	Kd (nM)
Cryptogein	1.02  ± 0.02	1.26  ± 0.01	24  ± 6
X24	1.04  ± 0.09	1.22  ± 0.02	52  ± 15
Y47F	0.92  ± 0.01	1.00  ± 0.04	304  ± 64
Y47G	1.01  ± 0.09	0.63  ± 0.01	1458  ± 56
Y87F	0.99  ± 0.04	0.21  ± 0.06	10391  ± 3792
Capsicein	0.85  ± 0.14a	0.80  ± 0.04a	758  ± 123

N, C_b, and Kd were used to describe the dynamic equilibrium of the DHE-elicitin interaction. They are linked according to the following equation: N = (C_b/A) × [(Kd/C_f) + 1], where C_b and C_f are the concentrations of bound and free DHE, respectively; Kd, the dissociation constant; A, the elicitin concentration; and N, the number of sterol binding sites. N and C_b were experimentally obtained. The numbers of binding sites (N) have been determined from the isolation of sterol-elicitin complexes and quantitation of its components according to the MATERIALS AND METHODS section. The total protein and sterol amount recovery was 94 ± 4% and 93 ± 10%, respectively. Data are expressed as mean of three independent replicates ± SD. C_b represents the concentration of DHE-elicitin complex determined fluorometrically (1.30 μM DHE, 2 μM elicitin, mean of three replicates ± SD). Kd was calculated from the above equation. 

^a Capsicein data were from Mikes et al., 1998.