Table I

Calculated and measured masses for b and y ions from MS/MS measurements of the 2297.092-Da tryptic fragment

y-ionm/z foundMH+ calculatedΔm (mDa)ResidueΔm (mDa)m/z foundMH+ calculatedb-ion
 y1147.113K22279.0832279.081b20
 y2261.138261.156−18N2150.986b19
 y3332.193332.1930A2036.943b18
 y4389.197389.215−18G1965.906b17
 y5552.283552.2785Y01908.8851908.885b16
 y6649.328649.331−3P−131745.8091745.822b15
 y7762.413762.415−2L211648.7901648.769b14
 y8849.438849.447−9S81535.6941535.685b13
 y9920.478920.484−6A−151448.6381448.653b12
y101049.5221049.526−4E191377.6371377.616b11
y111146.5711146.579−8P1248.573b10
y121203.5921203.601−9G−41151.5161151.520 b9
y131304.6361304.648−8T−51094.4941094.499 b8
y141361.6541361.670−16G1993.452993.451 b7
y151474.7391474.754−15L−21936.409936.430 b6
y161637.8181637.8171Y11823.357823.346 b5
y171800.8841800.8813Y9660.291660.282 b4
y181947.9701947.94921F1497.220497.219 b3
y192111.0222111.01210Y−5350.145350.150 b2
y202297.0862297.092−6W187.087 b1