Table 1. Interaction of Oregon-Green-labelled gelsolin with calponin was monitored by fluorescence as described in the legend of Figure 1.

Changes in the intensity of the fluorescence emission spectra of Oregon Green were recorded at various calponin concentrations in 0.1 M Tris/HCl buffer, pH 7.5, supplemented with 1 mM EGTA or 1 mM Ca²⁺. Percentage fluorescence decreases were extrapolated to infinite calponin concentration.

	Calponin h1		Calponin h3
Buffer conditions	Kd (nM)	Fluorescence decrease (%)	Kd (nM)	Fluorescence decrease (%)
pH 7.5 EGTA	16±4	47±5	130±20	40±4
pH 7.5 Ca2+	30±5	45±5	140±20	30±4