Table 2 Diagnostic features for the most abundant mass shifts detected in an open search of a pRBS-ID experiment

From: Detecting diagnostic features in MS/MS spectra of post-translationally modified peptides

peak apex

ion type

mass

remainder propensity

delta mod. mass

percent PSMs (mod)

percent PSMs (unmod)

avg. intensity (mod)

avg. intensity (unmod)

intensity fold change

226.0594

diagnostic

241.0626

  

37.76

26.3

17.55

8.35

3.02

226.0594

diagnostic

133.0500

  

27.28

15.1

7.89

4.44

3.21

226.0594

b

94.0344

26.86

−132.025

29.96

0.8

46.16

36.40

47.49

226.0594

b

77.0092

15.15

−149.050

15.96

1.4

24.54

17.53

15.96

226.0594

y

94.0362

14.48

−132.023

27.53

0.9

43.49

32.78

40.58

57.0216

b

57.0216

46.25

0

22.07

1.7

52.66

12.89

53.05

57.0216

y

57.0216

23.03

0

20.16

1.6

53.24

13.47

49.82

94.0168

diagnostic

164.0832

  

25.70

10.0

10.86

5.20

5.37

94.0168

diagnostic

215.0582

  

32.53

15.3

12.71

6.64

4.07

94.0168

diagnostic

241.0626

  

44.98

26.3

15.37

8.35

3.15

94.0168

b

94.0168

32.01

0

37.35

0.9

46.32

42.79

44.93

94.0168

b

−19.0638

19.08

−113.081

16.47

0.4

36.95

18.82

80.82

94.0168

b

77.0042

18.13

−17.0126

18.07

1.7

37.81

13.33

30.15

94.0168

y

94.0168

26.76

0

34.54

0.9

44.15

42.79

39.60

−48.0032

diagnostic

181.0986

  

27.63

16.3

9.95

4.63

3.64

−48.0032

b

−48.0032

41.80

0

42.8

1.3

77.96

15.23

100.00

−48.0032

y

−48.0032

24.37

0

41.25

1.3

64.48

20.08

100.00

  1. Remainder propensity scores are present only for b- and y- remainder masses. Features corresponding to the set of modified or unmodified PSMs used in comparisons are labeled as (mod) and (unmod), respectively. The difference between the MS1 mass shift and the observed fragment remainder masses (i.e., the lost mass) is enumerated in the “delta mod mass” column.