Table 1 The expected pH ranges per fraction were calculated according to the IPG strip supplier data and the OFFGEL well dimensions and compared with experimental pI obtained for plasma and secretome samples.

Fraction

Expected pH range

Peptide pI Average

s.d.

Peptide pI Average

s.d

1

3.35

3.61

4.11

0.40

4.24

0.92

2

3.61

3.88

4.17

0.56

4.11

0.31

3

3.88

4.14

4.29

0.22

4.24

0.26

4

4.14

4.40

4.53

0.32

4.40

0.19

5

4.40

4.66

4.67

0.42

4.56

0.33

6

4.66

4.93

4.77

0.45

4.90

0.84

7

4.93

5.19

5.25

0.59

5.55

0.54

8

5.19

5.45

5.61

0.36

5.33

0.65

9

5.45

5.71

5.61

0.39

5.50

0.41

10

5.71

5.98

5.71

0.67

5.66

0.39

11

5.98

6.24

5.81

0.70

5.88

0.36

12

6.24

6.50

5.99

0.70

5.88

0.42

13

6.50

6.76

6.10

0.75

6.11

0.61

14

6.76

7.03

6.20

0.85

6.22

0.72

15

7.03

7.29

6.48

0.80

6.78

1.24

16

7.29

7.55

6.63

0.78

6.73

0.87

17

7.55

7.81

6.89

0.87

6.79

0.88

18

7.81

8.08

7.75

1.13

6.88

0.95

19

8.08

8.34

8.20

1.26

7.64

1.81

20

8.34

8.60

8.36

1.03

7.78

1.70

21

8.60

8.86

8.33

1.05

8.33

1.20

22

8.86

9.13

8.31

1.23

8.42

0.97

23

9.13

9.39

8.49

1.06

8.77

1.04

24

9.39

9.65

8.48

1.42

9.22

1.13