i have tried so many things to try to solve this problem, but I just can\'t get
ID: 8067 • Letter: I
Question
i have tried so many things to try to solve this problem, but I just can't get it. Help, please.Given the masses of peptide fragments (mixture of the b- and y-ions), decipher the amino
acid sequence of the intact peptide (mass of the whole peptide = 1164.33). Usually 1-2 smallest
b- and y-ions are missed.
Peak # Mass (b- and y-ions)
1 1065.20
2 1036.16
3 964.09
4 923.00
5 877.01
6 835.92
7 745.82
8 698.78
9 630.73
10 551.60
11 483.55
12 436.51
13 346.41
14 305.32
Amino acid Single letter code Average residue mass
Alanine A 71.08
Arginine R 156.19
Asparagine N 114.10
Aspartic Acid D 115.09
Cysteine C 103.14
Glutamic Acid E 129.12
Glutamine Q 128.13
Glycine G 57.05
Histidine H 137.14
Isoleucine I 113.16
Leucine L 113.16
Lysine K 128.17
Methionine M 131.19
Phenylalanine F 147.18
Proline P 97.12
Serine S 87.08
Threonine T 101.11
Tryptophan W 186.21
Tyrosine Y 163.18
Valine V 99.13
Explanation / Answer
1. Ala- His-Pro- Ala- His-Pro- Ala- His-His-Lys Ser peptide chain mass is=1064 2 Ala- His-Pro- Ala- His-Pro- Ala- His-His-Ser peptide chain mass is=1034 3. Tyr-Ala-Cys-Gly-Ser-Tyr-Ala-Cys-Gly-Ser Ser peptide chain mass is=962.09 4. Ala- His-Pro- Ala- His-Asp ac- Ala- His-Pro= 923.03 5. Ala- His-His-Ser- Ala- His-His-Ser peptide chain mass is=875.01 6. Ala- His-Pro - Ala- His-His-Ser –Thr peptide chain mass is=834 7. Ala- His-Pro- Ala- His-Pro-Met Ser peptide chain mass is=743 8. . Ala- His-His- Ala- His-His peptide chain mass is=698.78 9. . Ala- His-Pro- Ala- His-Asp ac peptide chain mass is=628.73 10.Tyr-Gly-Gly-Phe-Lys peptide chain mass is=551 11.Tyrosine Y 163.18+ Alanine A 71.08+ Cysteine C 103.14+ Glycine G 57.05+serine87.08 Formula= H2N-Tyr-Ala-Cys-Gly-COOH +serine Name = Tyrosylalanylcysteinylglycine+serine peptide chain mass is 481 12. Ala- His-His-Ser peptide chain mass is=434.51 13. Ala- His-His peptide chain mass is=345.41 14 Alanine A 71.08+ Histidine H 137.14+ Proline P 97.12 Name = carnosine+ Proline Peptide chain mass= 305
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