Table 2.

TGF-β Family Members Identified in ActRII-Fc Pulldowns from Mouse and Human Sera

GI No.1	Protein Name	% Sequence Coverage2	Sequence	z3	Xcorr4
Mouse serum
111494000	Myostatin (mature)	49	(R)YPLTVDFEAFGWDWIIAPK	2+	4.83
			(K)ANYCSGECEFVFLQK	2+	4.55
			(K)MSPINMLYFNGK	2+	3.61
			(K)IPAMVVDR	2+	2.47
			(K)GSAGPCCTPTK	2+	2.30
111494000	Myostatin (propeptide)	24	(K)ALDENGHDLAVTFPGPGED-GLNPFLEVK	3+	4.57
			(K)QPESNLGIEIK	2+	2.31
			(K)TPTTVFVQILR	2+	3.29
			(K)TVLQNWLK	2+	2.54
296838	Inhibin α	40	(R)LLQRPPEEPAAHAFCHR	3+	3.90
			(K)PCCAALPGSMR	2+	3.30
			(R)STPSVPWPWSPAALR	2+	2.60
			(R)TTSDGGYSFK	2+	2.60
4160597	BMP-11	28	(R)YPLTVDFEAFGWDWIIAPK	2+	4.83
			(K)GSAGPCCTPTK	2+	2.30
50148	Inhibin βB	23	(R)GLNPGPVNSCCIPTK	2+	3.27
			(R)DVPNM* IVEECGCA5	2+	2.93
14714539	Inhibin βE	54	(R)RPLSLLYLDHNGNVVK	3+	5.31
			(K)ANNPWPAGSSCCVPTAR	2+	3.36
			(R)RTPTCEPETPLCCR	3+	3.34
			(K)TDVPDM* VVEACGCS	2+	3.30
			(R)TPTCEPETPLCCR	2+	3.29
74203474	Inhibin βC	28	(R)GSCCVPTSR	2+	2.68
			(R)GIDCQGASR	2+	2.63
			(K)TDIPDM* VVEACGCS	2+	2.53
Human serum
6649914	BMP-116	14	(R)RNLGLDCDEHSSESR	3+	2.58
75516754	BMP-106	7	(R)TPLYIDFK	2+	2.68
5031795	Inhibin βC	24	(R)AGGQCPACGGPTLELESQR	2+	4.63
			(R)GIDCQGGSR	2+	2.34
22761274	Inhibin βE	36	(K)ANNPWPASTSCCVPTAR	2+	3.47
			(R)DHYVDFQELGWR	2+	3.60
			(R)TPTCEPATPLCCR	2+	3.61

¹GI No., GenInfo Identifier used to access protein sequence records in NCBI.

²Percent sequence coverage represents the percent of the protein amino acid sequence that can be mapped by the identified peptides from MS.

³z is the charged state of the parent peptide ion.

⁴X_corris the Sequest search cross-correlation value. It increases with peptide length and charge.

⁵M*, Methionine oxidation.

⁶Annotated fragment ion spectra of these peptides are shown in Supplemental Fig. 1b (BMP-10) and 1c (BMP-11).