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Table 5 Mass spectrometric analysis of formic acid (FA) fraction immunoprecipitated with 4G8 from human brains reveal unique Aβ peaks.

From: Overlapping profiles of Aβ peptides in the Alzheimer's disease and pathological aging brains

Aβ Peptide

predicted MW

observed MW

AD (n= 16)

PA (n= 9)

NDC (n= 8)

1-18

2167.28

2165.21

1 (6.3%)

  

1-27

3134.27

3135.30

1 (6.3%)

  

E11-42

3317.90

3320.02

8 (50.0%)

7 (77.8%)

1 (12.5%)

1-29

3319.49

3320.87

1 (6.3%)

  

11-42

3335.90

3328.79

 

1 (11.1%)

 

9-40

3371.90

3373.39

3 (18.8%)

5 (55.6%)

4 (50%)

8-40

3458.98

3460.65

1 (6.3%)

1 (11.1%)

 

1-31

3503.72

3503.55

1 (6.3%)

  

9-42

3556.08

3557.85

1 (6.3%)

  

8-42

3643.15

3644.86

5 (31.3%)

 

1 (12.5%)

7-42

3758.24

3758.89

2 (12.5%)

  

1-34

3787.09

3786.56

1 (6.3%)

  

1-35

3918.29

3918.96

1 (6.3%)

  

4-40

4014.57

4016.85

1 (6.3%)

1 (11.1%)

 

1-36

4017.42

4018.25

1 (6.3%)

1 (11.1%)

 

5-42

4051.57

4053.59

4 (25.0%)

 

1 (12.5%)

1-37

4074.47

4075.25

1 (6.3%)

  

1-38

4131.52

4131.33

1 (6.3%)

1 (11.1%)

 

4-42

4198.74

4201.29

 

5 (55.6%)

2 (25%)

4-42 +16 Da

4214.74

4217.09

2 (12.5%)

1 (11.1%)

 

1-39

4230.65

4231.46

1 (6.3%)

  

E3-42

4309.90

4312.76

4 (25.0%)

3 (33.3%)

1 (12.5%)

1-40

4329.78

4331.85

8 (50.0%)

5 (55.6%)

2 (25%)

1-40 +16 Da

4345.78

4348.09

4 (25.0%)

  

1-42

4514.02

4516.70

10 (62.5%)

7 (77.8%)

4 (50%)

1-42 +16 Da

4530.02

4533.03

  

1 (12.5%)

  1. Human brain tissue, extracted with 70% FA, was sequentially immunoprecipitated with Ab9 and 4G8 antibodies to enrich different truncated or modified Aβ species. Mass spectrometric analysis shows unique Aβ peptides that 1) have not been previously reported in other mass spectrometric analyses of AD brains (underlined) 2) uniquely present in AD (bold font), PA (italicized font) or controls (bold and italicized font) are differentially highlighted. Predicted molecular weights and observed molecular weights have been calculated using ExPASy PeptideMass and ProteinChip Data Manager software (Bio-Rad), respectively. The number of subjects (AD, Alzheimer's disease; PA, Pathological aging; NDC, controls) displaying each uniquely identifiable Aβ peptide and the percentage of occurrence of such peptide corresponding to the total sample size is denoted. Aβ, amyloid β; MW, molecular weight; n, number.