TABLE 2.

Binding constants for Fst-type molecules to ligands determined through SPR

Surface	Analyte
	Fstl3	KD	-Fold over WT	Fst	KD	-Fold over WT
		nm			nm
Myostatin	WT	1.3	1.0	WT	6.3	1.0
	L24E	170	131	V15E	20	3.2
	L57E	2400	1846	F47E	21	3.3
	F60E	2400	1846	I51E	27	4.3
	L61E	1600	1231	F52E	25	4.0
	L57A	120	92	F47A	59	9.4
	F60A	56	43	I51A	21	3.3
	L61A	410	315	F52A	54	8.6
Activin A	WT	0.14	1.0	WT	0.02	1.0
	L24E	0.56	4.0	V15E	0.02	1.0
	L57E	150	1071	F47E	0.04	2.0
	F60E	98	700	I51E	0.03	1.5
	L61E	140	1000	F52E	0.02	1.0
	L57A	59	421	F47A	0.05	2.5
	F60A	93	664	I51A	0.02	1.0
	L61A	43	307	F52A	0.02	1.0