Table 1.

Dissociation Constants for Ca²⁺-Binding to S100A4

	dissociation constant (μM)
	EF1	EF2
wild-type S100A4	≥574a	2.6 ± 1.0a
Mero-S100A4	≥447a	0.4 ± 0.3a
	≥830b	≤0.5b

^aThe dissociation constants were determined using competition studies of Ca²⁺ with the chromophoric chelator 5,5′Br₂-BAPTA.

^bThe dissociation constants were determined by monitoring the fluorescence of the Mero-S100A4 during titration with Ca²⁺. The data from both assays were fit to a stepwise macroscopic binding equation for two sites (22).