TABLE 2.

Assignment of the digestive fragments of mature and prefibrillar intermediate fibrils monitored without the reduction of disulfide bonds

Fibrils were depolymerized into monomers by the addition of dimethyl sulfoxide after proteolytic treatment and then used for measurement.

Observed m/za	Theoretical m/za	Assignment
Mature fibrils
5174.1	5174.0	GIVEQCCASVCSLYQLENYCN (A:1–21) plus FVNQHLCGSHLVEALYLVCGERGFF (B:1–25)
Prefibrillar intermediate
2560.959	2561.140	GIVEQCCASVCSL (A:1–13) plus FVNQHLCGSHL (B:1–11)
2789.168	2789.251	GIVEQCCASVCSL (A:1–13) plus FVNQHLCGSHLVE (B:1–13)
2852.156	2852.262	GIVEQCCASVCSLYQ (A:1–15) plus FVNQHLCGSHL (B:1–11)

^a For the mature fibrils, observed and theoretical m/z values are represented as averaged masses because mass resolution of the observed peak is insufficient for accurate determination of its monoisotopic mass. For the prefibrillar intermediate, observed and theoretical m/z values are represented as monoisotopic masses. The m/z value for intact insulin (i.e., A:1–21 plus B:1–30) was excluded from the list.